fix(api): fix uvicorn config loop arg

We were providing the loop itself, not the kind of loop. This didn't appear to cause any issues whatsoever, but now it's correct.

invokeai/app/api_app.py

@@ -245,7 +245,7 @@ def invoke_api():
         app=app,
         host=app_config.host,
         port=port,
-        loop=loop,
+        loop="asyncio",
         log_level=app_config.log_level,
     )
     server = uvicorn.Server(config)