refac: modernize type annotations (PEP 604 / PEP 585)

backend/open_webui/retrieval/web/bing.py

@@ -1,10 +1,11 @@
+import argparse
 import logging
 import os
 from pprint import pprint
 from typing import Optional
+
 import requests
 from open_webui.retrieval.web.main import SearchResult, get_filtered_results
-import argparse
 
 log = logging.getLogger(__name__)
 """