feat: keep existing users signed in when moving to native SDK

[DontGiveAFck]

Plugin(s)

• [ ] Analytics
• [ ] App
• [ ] App Check
• [X] Authentication
• [ ] Crashlytics
• [ ] Cloud Firestore
• [ ] Cloud Functions
• [ ] Cloud Messaging
• [ ] Cloud Storage
• [ ] Performance
• [ ] Remote Config

Current problem

Users that were signed in with js sdk in old app version should be kept signed in in new app version that uses native sdk.

Preferred solution

Not sure what exactly should be implemented, maybe signInWithCredential method should help - so we can get token id with js sdk and use it to login with newly implemented signInWithCredential in native sdk

Alternative options

No response

Additional context

No response

Before submitting

• [X] I have read and followed the feature request guidelines.
• [X] I have attached links to possibly related issues and discussions.

[robingenz]

I'm not sure if this is possible. It is definitely not possible with all OAuth providers. Even for users who are logged in with email/password, I can't think of a possibility right now. You often need information such as the access token or a secret that is only available at the time of login. Feel free to create a PR and i will take a look.