fix: fix passage listing for sources (#894)

letta/server/server.py

@@ -1000,8 +1000,8 @@ class SyncServer(Server):
         return passage_count, document_count
 
     def list_data_source_passages(self, user_id: str, source_id: str) -> List[Passage]:
-        warnings.warn("list_data_source_passages is not yet implemented, returning empty list.", category=UserWarning)
-        return []
+        # TODO: move this query into PassageManager
+        return self.agent_manager.list_passages(actor=self.user_manager.get_user_or_default(user_id=user_id), source_id=source_id)
 
     def list_all_sources(self, actor: User) -> List[Source]:
         """List all sources (w/ extra metadata) belonging to a user"""