enh: kb metadata search

backend/open_webui/retrieval/vector/dbs/elasticsearch.py

@@ -153,7 +153,7 @@ class ElasticsearchClient(VectorDBBase):
 
     # Status: works
     def search(
-        self, collection_name: str, vectors: list[list[float]], limit: int
+        self, collection_name: str, vectors: list[list[float]], filter: Optional[dict] = None, limit: int = 10
     ) -> Optional[SearchResult]:
         query = {
             "size": limit,