refactor(app_configuration): update localization key and improve UI naming

- Update localization key for saved feed filter limits tile
- Improve UI naming by changing "Filter Limits" to "Filters Limit"

Author: fulleni

lib/app_configuration/view/tabs/feed_configuration_tab.dart

@@ -92,8 +92,8 @@ class _FeedConfigurationTabState extends State<FeedConfigurationTab> {
           builder: (context, expandedIndex, child) {
             const tileIndex = 1;
             return ExpansionTile(
-              key: ValueKey('savedHeadlinesFilterLimitsTile_$expandedIndex'),
-              title: Text(l10n.savedFeedFilterLimitsTitle),
+              key: ValueKey('savedFeedFilterLimitsTile_$expandedIndex'),
+              title: Text(l10n.savedFeedFiltersLimitLabel),
               childrenPadding: const EdgeInsetsDirectional.only(
                 start: AppSpacing.lg,
                 top: AppSpacing.md,