use better names + remove unused code

lib/ui/settings/details_section_widget.dart

@@ -121,8 +121,8 @@ class _DetailsSectionWidgetState extends State<DetailsSectionWidget> {
     }
 
     final usedSpaceInGB =
-        convertBytesToGB(userDetails.getFamilyOrPersonalUsage());
-    final totalStorageInGB = convertBytesToGB(userDetails.getTotalStorage());
+        convertBytesToGBs(userDetails.getFamilyOrPersonalUsage());
+    final totalStorageInGB = convertBytesToGBs(userDetails.getTotalStorage());
 
     return Padding(
       padding: const EdgeInsets.only(
@@ -279,7 +279,7 @@ class _DetailsSectionWidgetState extends State<DetailsSectionWidget> {
                         RichText(
                           text: TextSpan(
                             text:
-                                "${shouldShowFreeSpaceInMBs ? convertBytesToMB(freeSpaceInBytes) : _roundedFreeSpace(totalStorageInGB, usedSpaceInGB)}",
+                                "${shouldShowFreeSpaceInMBs ? convertBytesToMBs(freeSpaceInBytes) : _roundedFreeSpace(totalStorageInGB, usedSpaceInGB)}",
                             style: getEnteTextTheme(context)
                                 .mini
                                 .copyWith(color: textFaintDark),
@@ -306,6 +306,7 @@ class _DetailsSectionWidgetState extends State<DetailsSectionWidget> {
 
   num _roundedFreeSpace(num totalStorageInGB, num usedSpaceInGB) {
     int fractionDigits;
+    //subtracting usedSpace from totalStorage in GB instead of converting from bytes so that free space and used space adds up in the UI
     final freeSpace = totalStorageInGB - usedSpaceInGB;
     //show one decimal place if free space is less than 10GB
     if (freeSpace < 10) {

lib/utils/data_util.dart

@@ -1,11 +1,5 @@
 import 'dart:math';
 
-double convertBytesToGBs(final int bytes, {int precision = 2}) {
-  return double.parse(
-    (bytes / (1024 * 1024 * 1024)).toStringAsFixed(precision),
-  );
-}
-
 final storageUnits = ["bytes", "KB", "MB", "GB"];
 
 String convertBytesToReadableFormat(int bytes) {
@@ -26,7 +20,7 @@ String formatBytes(int bytes, [int decimals = 2]) {
 }
 
 //shows decimals only if less than 10GB & omits decimal if decimal is 0
-num convertBytesToGB(int bytes) {
+num convertBytesToGBs(int bytes) {
   const tenGBinBytes = 10737418240;
   int precision = 0;
   if (bytes < tenGBinBytes) {
@@ -37,6 +31,6 @@ num convertBytesToGB(int bytes) {
   return bytesInGB;
 }
 
-int convertBytesToMB(int bytes) {
+int convertBytesToMBs(int bytes) {
   return (bytes / pow(1024, 2)).round();
 }