fix: use keyword argument for IndicesClient.refresh() for opensearch-py 3.x (open-webui#21248)

In opensearch-py >= 3.0.0, IndicesClient.refresh() no longer accepts the
index name as a positional argument. This causes a TypeError when
uploading documents to knowledge bases with OpenSearch backend.

Changes positional arguments to keyword arguments (index=...) in all
three refresh() calls in the OpenSearch vector DB client.

Fixes open-webui#20649

Author: veeceey

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

@@ -211,7 +211,7 @@ def insert(self, collection_name: str, items: list[VectorItem]):
                 for item in batch
             ]
             bulk(self.client, actions)
-        self.client.indices.refresh(self._get_index_name(collection_name))
+        self.client.indices.refresh(index=self._get_index_name(collection_name))
 
     def upsert(self, collection_name: str, items: list[VectorItem]):
         self._create_index_if_not_exists(
@@ -234,7 +234,7 @@ def upsert(self, collection_name: str, items: list[VectorItem]):
                 for item in batch
             ]
             bulk(self.client, actions)
-        self.client.indices.refresh(self._get_index_name(collection_name))
+        self.client.indices.refresh(index=self._get_index_name(collection_name))
 
     def delete(
         self,
@@ -263,7 +263,7 @@ def delete(
             self.client.delete_by_query(
                 index=self._get_index_name(collection_name), body=query_body
             )
-        self.client.indices.refresh(self._get_index_name(collection_name))
+        self.client.indices.refresh(index=self._get_index_name(collection_name))
 
     def reset(self):
         indices = self.client.indices.get(index=f"{self.index_prefix}_*")