[FR]: firebaseui within unity SDK ?

### Description

Are there plan to add firebaseui to the unity SDK ? if not could tutorial be made to easily integrate the Android/iOS packages with it ?

### API Proposal

Easily integrate firebaseUI

### Firebase Product(s)

Firebase Auth (in our usecase)

### Targeted Platform(s)

Android / iOS

Start by reviewing the Unity SDK's Firebase Auth integration and the Android and iOS package integration paths mentioned in the issue. Compare whether FirebaseUI can be supported directly or whether a tutorial is the appropriate outcome. Done means a documented feasibility decision and, if applicable, an integration tutorial for the targeted platforms.

Written by the indexing model from the issue text.