chore: user header forward minimize code changes throughout codebase (#19392)

* Update external.py

* remove unused imports

* Update ollama.py

* Update ollama.py

* Update ollama.py

* Update openai.py

backend/open_webui/routers/audio.py

@@ -16,7 +16,6 @@ import aiohttp
 import aiofiles
 import requests
 import mimetypes
-from urllib.parse import urljoin, quote
 
 from fastapi import (
     Depends,