refac/fix: files batch/add endpoint

backend/open_webui/routers/knowledge.py

@@ -708,7 +708,7 @@ async def reset_knowledge_by_id(id: str, user=Depends(get_verified_user)):
 
 
 @router.post("/{id}/files/batch/add", response_model=Optional[KnowledgeFilesResponse])
-def add_files_to_knowledge_batch(
+async def add_files_to_knowledge_batch(
     request: Request,
     id: str,
     form_data: list[KnowledgeFileIdForm],
@@ -748,7 +748,7 @@ def add_files_to_knowledge_batch(
 
     # Process files
     try:
-        result = process_files_batch(
+        result = await process_files_batch(
             request=request,
             form_data=BatchProcessFilesForm(files=files, collection_name=id),
             user=user,