refactor(filter): make reset button local and intelligently disabled

Refactors the "Reset" button on the `HeadlinesFilterPage`.

The button now dispatches a `FilterSelectionsCleared` event to the local `HeadlinesFilterBloc`, clearing the selections on the page without exiting. This provides a more intuitive user experience.

The button is also now intelligently disabled when there are no active selections to clear.

Author: fulleni

lib/headlines-feed/view/headlines_filter_page.dart

@@ -219,6 +219,13 @@ class _HeadlinesFilterViewState extends State<_HeadlinesFilterView> {
           builder: (context, filterState) {
             final theme = Theme.of(context);
 
+            // Determine if the reset button should be enabled. It's enabled only
+            // if there are active selections to clear.
+            final isResetEnabled =
+                filterState.selectedTopics.isNotEmpty ||
+                filterState.selectedSources.isNotEmpty ||
+                filterState.selectedCountries.isNotEmpty;
+
             // Determine if the "Apply" button should be enabled.
             final isFilterEmpty =
                 filterState.selectedTopics.isEmpty &&
@@ -259,21 +266,16 @@ class _HeadlinesFilterViewState extends State<_HeadlinesFilterView> {
                   style: theme.textTheme.titleLarge,
                 ),
                 actions: [
-                  // Reset All Filters Button
+                  // Reset button to clear local selections on this page.
                   IconButton(
                     icon: const Icon(Icons.refresh),
                     tooltip: l10n.headlinesFeedFilterResetButton,
-                    onPressed: () {
-                      // Dispatch event to clear filters in the feed bloc
-                      // and trigger a refresh to the "All" state.
-                      context.read<HeadlinesFeedBloc>().add(
-                        AllFilterSelected(
-                          adThemeStyle: AdThemeStyle.fromTheme(theme),
-                        ),
-                      );
-                      // Close the filter page.
-                      context.pop();
-                    },
+                    // The button is disabled if there are no selections to clear.
+                    onPressed: isResetEnabled
+                        ? () => context.read<HeadlinesFilterBloc>().add(
+                            const FilterSelectionsCleared(),
+                          )
+                        : null,
                   ),
                   // Apply Filters Button
                   IconButton(