I have a mobile app in React Native. I setUserId when user logs in or registers. I understand that during this session all sent events are personalized. But when user closes the app and opens it in 2 days, he does not need to login, so I do not setUserId manually. But amplitude session is new. I send events in new session. Are these events pesonalized? If yes, how does it happen? Is this data stored on client’s side? If yes, for how long is it stored there?