feat(feed): reset filter on refresh

- Reset filter after refreshing
- Improves user experience

Author: fulleni

lib/headlines-feed/bloc/headlines_feed_bloc.dart

@@ -155,6 +155,7 @@ class HeadlinesFeedBloc extends Bloc<HeadlinesFeedEvent, HeadlinesFeedState> {
           feedItems: processedFeedItems,
           hasMore: headlineResponse.hasMore,
           cursor: headlineResponse.cursor,
+          filter: const HeadlineFilter(), // Ensure filter is reset
         ),
       );