Add close method override in DevicesCubit

Add override for close method in DevicesCubit to set _isClosed flag and call super.close(). This prevents further operations after closing.

lib/features/devices/bloc/devices_cubit.dart

@@ -24,6 +24,13 @@ class DevicesCubit extends Cubit<DevicesState> {
   DevicesCubit() : super(DevicesInitial()) {
     fetchGroups(SpacesCubit.selectedSpace!.id!);
   }
+  bool _isClosed = false;
+
+  @override
+  Future<void> close() {
+    _isClosed = true;
+    return super.close();
+  }
 
   static DevicesCubit get(context) => BlocProvider.of(context);
 
@@ -229,6 +236,8 @@ class DevicesCubit extends Cubit<DevicesState> {
   }
 
   fetchGroups(int spaceId) async {
+    if (_isClosed) return;
+
     try {
       emit(DevicesCategoriesLoading());
       allCategories = await DevicesAPI.fetchGroups(spaceId);