make carousel more stable

lib/services/data_service/data_service_badges.dart

@@ -55,7 +55,6 @@ extension DataServiceBadges on DataService {
     bool onlyIncomplete = false,
   }) async {
     _isClassClearanceProgressLoading = true;
-    if (!append) _classClearanceProgress = [];
     try {
       final onlyIncompleteParam =
           onlyIncomplete ? '&only_incomplete=true' : '';
@@ -84,7 +83,6 @@ extension DataServiceBadges on DataService {
       _classClearanceHasMore = items.length >= limit;
     } catch (e) {
       debugPrint('Failed to fetch class clearance progress: $e');
-      if (!append) _classClearanceProgress = [];
       _classClearanceHasMore = false;
     } finally {
       _isClassClearanceProgressLoading = false;