Initialize the notification service only on Android

lib/services/notification_service.dart

@@ -11,6 +11,7 @@ class NotificationService {
       FlutterLocalNotificationsPlugin();
 
   Future<void> init() async {
+    
     const AndroidInitializationSettings initializationSettingsAndroid =
         AndroidInitializationSettings('notification_icon');
     final InitializationSettings initializationSettings =