fix: only throw notifications for sync to internal users

mobile/lib/utils/bg_task_utils.dart

@@ -4,6 +4,7 @@ import "package:logging/logging.dart";
 import "package:permission_handler/permission_handler.dart";
 import "package:photos/db/upload_locks_db.dart";
 import "package:photos/main.dart";
+import "package:photos/service_locator.dart";
 import "package:photos/utils/file_uploader.dart";
 import "package:shared_preferences/shared_preferences.dart";
 import "package:workmanager/workmanager.dart" as workmanager;
@@ -55,8 +56,7 @@ class BgTaskUtils {
     try {
       await workmanager.Workmanager().initialize(
         callbackDispatcher,
-        isInDebugMode:
-            true, // TODO(prateekmedia): Remove when merged to production
+        isInDebugMode: flagService.internalUser,
       );
       await workmanager.Workmanager().registerPeriodicTask(
         backgroundTaskIdentifier,