fix(headlines-search): update country item widget navigation

- Replace deprecated EntityDetailsPageArguments with entityId and contentType
- Ensure proper navigation to country details page

Author: fulleni

lib/headlines-search/widgets/country_item_widget.dart

@@ -23,7 +23,10 @@ class CountryItemWidget extends StatelessWidget {
       onTap: () {
         context.push(
           Routes.countryDetails,
-          extra: EntityDetailsPageArguments(entity: country),
+          extra: EntityDetailsPageArguments(
+            entityId: country.id,
+            contentType: ContentType.country,
+          ),
         );
       },
     );