Fix bug: init sharedPref and call sync during init

lib/main.dart

@@ -143,7 +143,7 @@ Future<void> _init(bool isBackground) async {
   await RemoteSyncService.instance.init();
   await SyncService.instance.init();
   await MemoriesService.instance.init();
-  FeatureFlagService.instance.sync();
+  FeatureFlagService.instance.init();
   _logger.info("Initialization done");
   _initializationStatus.complete();
 }

lib/services/feature_flag_service.dart

@@ -17,6 +17,7 @@ class FeatureFlagService {
 
   Future<void> init() async {
     _prefs = await SharedPreferences.getInstance();
+    await sync();
   }
 
   bool disableCFWorker() {