fix: email claim constant

Author: dongs0104

backend/open_webui/utils/oauth.py

@@ -234,7 +234,7 @@ async def handle_callback(self, request, provider, response):
             log.warning(f"OAuth callback error: {e}")
             raise HTTPException(400, detail=ERROR_MESSAGES.INVALID_CRED)
         user_data: UserInfo = token.get("userinfo")
-        if not user_data or "email" not in user_data:
+        if not user_data or auth_manager_config.OAUTH_EMAIL_CLAIM not in user_data:
             user_data: UserInfo = await client.userinfo(token=token)
         if not user_data:
             log.warning(f"OAuth callback failed, user data is missing: {token}")