remove prefix letters from indentifier names

lib/models/subscription.dart

@@ -2,10 +2,10 @@
 
 import 'dart:convert';
 
-const kFreeProductID = "free";
-const kStripe = "stripe";
-const kAppStore = "appstore";
-const kPlayStore = "playstore";
+const freeProductID = "free";
+const stripe = "stripe";
+const appStore = "appstore";
+const playStore = "playstore";
 
 class Subscription {
   final int id;

lib/ui/payment/payment_web_page.dart

@@ -218,7 +218,7 @@ class _PaymentWebPageState extends State<PaymentWebPage> {
       final response = await billingService.verifySubscription(
         widget.planId,
         checkoutSessionID,
-        paymentProvider: kStripe,
+        paymentProvider: stripe,
       );
       await _dialog.hide();
       if (response != null) {

lib/ui/payment/skip_subscription_widget.dart

@@ -42,7 +42,7 @@ class SkipSubscriptionWidget extends StatelessWidget {
             (route) => false,
           );
           BillingService.instance
-              .verifySubscription(kFreeProductID, "", paymentProvider: "ente");
+              .verifySubscription(freeProductID, "", paymentProvider: "ente");
         },
         child: const Text("Continue on free plan"),
       ),

lib/ui/payment/stripe_subscription_page.dart

@@ -67,7 +67,7 @@ class _StripeSubscriptionPageState extends State<StripeSubscriptionPage> {
       _currentSubscription = userDetails.subscription;
       _showYearlyPlan = _currentSubscription.isYearlyPlan();
       _hasActiveSubscription = _currentSubscription.isValid();
-      _isStripeSubscriber = _currentSubscription.paymentProvider == kStripe;
+      _isStripeSubscriber = _currentSubscription.paymentProvider == stripe;
       return _filterStripeForUI().then((value) {
         _hasLoadedData = true;
         setState(() {});
@@ -103,7 +103,7 @@ class _StripeSubscriptionPageState extends State<StripeSubscriptionPage> {
     if (widget.isOnboarding &&
         _currentSubscription != null &&
         _currentSubscription.isValid() &&
-        _currentSubscription.productID != kFreeProductID) {
+        _currentSubscription.productID != freeProductID) {
       Navigator.of(context).popUntil((route) => route.isFirst);
     }
   }
@@ -204,7 +204,7 @@ class _StripeSubscriptionPageState extends State<StripeSubscriptionPage> {
       widgets.add(ValidityWidget(currentSubscription: _currentSubscription));
     }
 
-    if (_currentSubscription.productID == kFreeProductID) {
+    if (_currentSubscription.productID == freeProductID) {
       if (widget.isOnboarding) {
         widgets.add(SkipSubscriptionWidget(freePlan: _freePlan));
       }
@@ -216,24 +216,24 @@ class _StripeSubscriptionPageState extends State<StripeSubscriptionPage> {
       widgets.add(_stripeRenewOrCancelButton());
     }
 
-    if (_currentSubscription.productID != kFreeProductID) {
+    if (_currentSubscription.productID != freeProductID) {
       widgets.addAll([
         Align(
           alignment: Alignment.center,
           child: GestureDetector(
             onTap: () async {
               switch (_currentSubscription.paymentProvider) {
-                case kStripe:
+                case stripe:
                   await _launchStripePortal();
                   break;
-                case kPlayStore:
+                case playStore:
                   launchUrlString(
                     "https://play.google.com/store/account/subscriptions?sku=" +
                         _currentSubscription.productID +
                         "&package=io.ente.photos",
                   );
                   break;
-                case kAppStore:
+                case appStore:
                   launchUrlString("https://apps.apple.com/account/billing");
                   break;
                 default:
@@ -325,7 +325,7 @@ class _StripeSubscriptionPageState extends State<StripeSubscriptionPage> {
   }
 
   Future<void> _launchFamilyPortal() async {
-    if (_userDetails.subscription.productID == kFreeProductID) {
+    if (_userDetails.subscription.productID == freeProductID) {
       await showErrorDialog(
         context,
         "Now you can share your storage plan with your family members!",
@@ -438,7 +438,7 @@ class _StripeSubscriptionPageState extends State<StripeSubscriptionPage> {
               // payment providers
               if (!_isStripeSubscriber &&
                   _hasActiveSubscription &&
-                  _currentSubscription.productID != kFreeProductID) {
+                  _currentSubscription.productID != freeProductID) {
                 showErrorDialog(
                   context,
                   "Sorry",
@@ -540,7 +540,7 @@ class _StripeSubscriptionPageState extends State<StripeSubscriptionPage> {
     // don't add current plan if it's monthly plan but UI is showing yearly plans
     // and vice versa.
     if (_showYearlyPlan != _currentSubscription.isYearlyPlan() &&
-        _currentSubscription.productID != kFreeProductID) {
+        _currentSubscription.productID != freeProductID) {
       return;
     }
     int activePlanIndex = 0;

lib/ui/payment/subscription_common_widgets.dart

@@ -93,7 +93,7 @@ class ValidityWidget extends StatelessWidget {
       DateTime.fromMicrosecondsSinceEpoch(currentSubscription.expiryTime),
     );
     var message = "Renews on $endDate";
-    if (currentSubscription.productID == kFreeProductID) {
+    if (currentSubscription.productID == freeProductID) {
       message = "Free plan valid till $endDate";
     } else if (currentSubscription.attributes?.isCancelled ?? false) {
       message = "Your subscription will be cancelled on $endDate";

lib/ui/payment/subscription_page.dart

@@ -160,7 +160,7 @@ class _SubscriptionPageState extends State<SubscriptionPage> {
       _hasActiveSubscription = _currentSubscription.isValid();
       final billingPlans = await _billingService.getBillingPlans();
       _isActiveStripeSubscriber =
-          _currentSubscription.paymentProvider == kStripe &&
+          _currentSubscription.paymentProvider == stripe &&
               _currentSubscription.isValid();
       _plans = billingPlans.plans.where((plan) {
         final productID = _isActiveStripeSubscriber
@@ -210,7 +210,7 @@ class _SubscriptionPageState extends State<SubscriptionPage> {
       widgets.add(ValidityWidget(currentSubscription: _currentSubscription));
     }
 
-    if (_currentSubscription.productID == kFreeProductID) {
+    if (_currentSubscription.productID == freeProductID) {
       if (widget.isOnboarding) {
         widgets.add(SkipSubscriptionWidget(freePlan: _freePlan));
       }
@@ -218,7 +218,7 @@ class _SubscriptionPageState extends State<SubscriptionPage> {
     }
 
     if (_hasActiveSubscription &&
-        _currentSubscription.productID != kFreeProductID) {
+        _currentSubscription.productID != freeProductID) {
       widgets.addAll([
         Align(
           alignment: Alignment.center,
@@ -345,7 +345,7 @@ class _SubscriptionPageState extends State<SubscriptionPage> {
     bool foundActivePlan = false;
     final List<Widget> planWidgets = [];
     if (_hasActiveSubscription &&
-        _currentSubscription.productID == kFreeProductID) {
+        _currentSubscription.productID == freeProductID) {
       foundActivePlan = true;
       planWidgets.add(
         SubscriptionPlanWidget(
@@ -392,7 +392,7 @@ class _SubscriptionPageState extends State<SubscriptionPage> {
               }
               final isCrossGradingOnAndroid = Platform.isAndroid &&
                   _hasActiveSubscription &&
-                  _currentSubscription.productID != kFreeProductID &&
+                  _currentSubscription.productID != freeProductID &&
                   _currentSubscription.productID != plan.androidID;
               if (isCrossGradingOnAndroid) {
                 final existingProductDetailsResponse =
@@ -470,7 +470,7 @@ class _SubscriptionPageState extends State<SubscriptionPage> {
 
   // todo: refactor manage family in common widget
   Future<void> _launchFamilyPortal() async {
-    if (_userDetails.subscription.productID == kFreeProductID) {
+    if (_userDetails.subscription.productID == freeProductID) {
       await showErrorDialog(
         context,
         "Share your storage plan with your family members!",