enh: delete_file query param

backend/open_webui/routers/knowledge.py

@@ -1,6 +1,6 @@
 from typing import List, Optional
 from pydantic import BaseModel
-from fastapi import APIRouter, Depends, HTTPException, status, Request
+from fastapi import APIRouter, Depends, HTTPException, status, Request, Query
 import logging
 
 from open_webui.models.knowledge import (
@@ -492,6 +492,7 @@ def update_file_from_knowledge_by_id(
 def remove_file_from_knowledge_by_id(
     id: str,
     form_data: KnowledgeFileIdForm,
+    delete_file: bool = Query(True),
     user=Depends(get_verified_user),
 ):
     knowledge = Knowledges.get_knowledge_by_id(id=id)
@@ -528,6 +529,7 @@ def remove_file_from_knowledge_by_id(
         log.debug(e)
         pass
 
+    if delete_file:
         try:
             # Remove the file's collection from vector database
             file_collection = f"file-{form_data.file_id}"