fix(headlines-search): update topic item widget to use correct arguments

- Replace EntityDetailsPageArguments with individual parameters
- Add entityId and contentType to EntityDetailsPageArguments
- Update Routes.topicDetails to use new argument structure

Author: fulleni

lib/headlines-search/widgets/topic_item_widget.dart

@@ -24,7 +24,10 @@ class TopicItemWidget extends StatelessWidget {
       onTap: () {
         context.push(
           Routes.topicDetails,
-          extra: EntityDetailsPageArguments(entity: topic),
+          extra: EntityDetailsPageArguments(
+            entityId: topic.id,
+            contentType: ContentType.topic,
+          ),
         );
       },
     );