Fix audit get_current_user

get_current_user has 4 args not 3 args:
```
get_current_user(
    request: Request,
    response: Response,
    background_tasks: BackgroundTasks,
    auth_token: HTTPAuthorizationCredentials = Depends(bearer_security)
```

backend/open_webui/utils/audit.py

@@ -195,7 +195,7 @@ class AuditLoggingMiddleware:
 
         try:
             user = get_current_user(
-                request, None, get_http_authorization_cred(auth_header)
+                request, None, None, get_http_authorization_cred(auth_header)
             )
             return user
         except Exception as e: