remove unused import in main

backend/apps/web/main.py

@@ -1,7 +1,6 @@
 from fastapi import FastAPI, Depends
 from fastapi.routing import APIRoute
 from fastapi.middleware.cors import CORSMiddleware
-from starlette.middleware.authentication import AuthenticationMiddleware
 from apps.web.routers import auths, users, chats, modelfiles, utils
 from config import WEBUI_VERSION, WEBUI_AUTH
 from utils.utils import verify_auth_token