refactor(content_management): remove country search functionality

- Remove _onCountrySearchChanged method and its associated event
- Remove droppable transformer from CreateHeadlineCountrySearchChanged event
- Adjust country load more functionality to not consider search term

Author: fulleni

lib/content_management/bloc/create_headline/create_headline_bloc.dart

@@ -35,10 +35,6 @@ class CreateHeadlineBloc
     on<CreateHeadlineCountryChanged>(_onCountryChanged);
     on<CreateHeadlineStatusChanged>(_onStatusChanged);
     on<CreateHeadlineSubmitted>(_onSubmitted);
-    on<CreateHeadlineCountrySearchChanged>(
-      _onCountrySearchChanged,
-      transformer: droppable(),
-    );
     on<CreateHeadlineLoadMoreCountriesRequested>(_onLoadMoreCountriesRequested);
   }
 
@@ -195,37 +191,6 @@ class CreateHeadlineBloc
     }
   }
 
-  Future<void> _onCountrySearchChanged(
-    CreateHeadlineCountrySearchChanged event,
-    Emitter<CreateHeadlineState> emit,
-  ) async {
-    await Future<void>.delayed(_searchDebounceDuration);
-    emit(state.copyWith(countrySearchTerm: event.searchTerm));
-    try {
-      final countriesResponse = await _countriesRepository.readAll(
-        filter: event.searchTerm.isNotEmpty ? {'name': event.searchTerm} : null,
-        sort: [const SortOption('name', SortOrder.asc)],
-      );
-
-      emit(
-        state.copyWith(
-          countries: countriesResponse.items,
-          countriesCursor: countriesResponse.cursor,
-          countriesHasMore: countriesResponse.hasMore,
-        ),
-      );
-    } on HttpException catch (e) {
-      emit(state.copyWith(status: CreateHeadlineStatus.failure, exception: e));
-    } catch (e) {
-      emit(
-        state.copyWith(
-          status: CreateHeadlineStatus.failure,
-          exception: UnknownException('An unexpected error occurred: $e'),
-        ),
-      );
-    }
-  }
-
   Future<void> _onLoadMoreCountriesRequested(
     CreateHeadlineLoadMoreCountriesRequested event,
     Emitter<CreateHeadlineState> emit,
@@ -239,9 +204,6 @@ class CreateHeadlineBloc
         pagination: state.countriesCursor != null
             ? PaginationOptions(cursor: state.countriesCursor)
             : null,
-        filter: state.countrySearchTerm.isNotEmpty
-            ? {'name': state.countrySearchTerm}
-            : null,
         sort: [const SortOption('name', SortOrder.asc)],
       );