chore: remove FeedsStateNotifier

The FeedsStateNotifier class was identical to StateNotifier and thus redundant. This commit removes FeedsStateNotifier and updates ActivityReactionListStateNotifier to directly extend StateNotifier.

Author: xsahil03x

packages/stream_feeds/lib/src/state/activity_reaction_list_state.dart

@@ -6,7 +6,6 @@ import 'package:stream_core/stream_core.dart';
 import '../models/feeds_reaction_data.dart';
 import '../models/pagination_data.dart';
 import '../models/query_configuration.dart';
-import '../utils/feeds_state_notifier.dart';
 import 'query/activity_reactions_query.dart';
 
 part 'activity_reaction_list_state.freezed.dart';
@@ -15,7 +14,8 @@ part 'activity_reaction_list_state.freezed.dart';
 ///
 /// Provides methods to update the activity reaction list state in response to data changes
 /// and real-time events from the Stream Feeds API.
-class ActivityReactionListStateNotifier extends FeedsStateNotifier<ActivityReactionListState> {
+class ActivityReactionListStateNotifier
+    extends StateNotifier<ActivityReactionListState> {
   ActivityReactionListStateNotifier({
     required ActivityReactionListState initialState,
   }) : super(initialState);