refactor(services): Use constant for remote config ID

- Replaced hardcoded ID with constant.
- Improved code readability and maintainability.

Author: fulleni

lib/src/services/default_user_preference_limit_service.dart

@@ -24,7 +24,7 @@ class DefaultUserPreferenceLimitService implements UserPreferenceLimitService {
   final Logger _log;
 
   // Assuming a fixed ID for the RemoteConfig document
-  static const String _remoteConfigId = 'remote_config';
+  static const String _remoteConfigId = kRemoteConfigId;
 
   @override
   Future<void> checkAddItem(