Firebase custom token auth

[Umair-Manzoor-47]

Github Ticket : #1703

1. Send credentials to backend.
2. onComplete auth from backend send token to this signInWithCustomAuth Action.
3. it Signs in Existing User if already exists or Creates a new one if User doesn't exists already.
4. User is now Authenticated and Signed in on firebase.
   Implemented sign in with custom firebase authentication token

    signInWithCustomAuth:
      token: {firebase token form backend server}
      onAuthenticated:
        executeCode:
          body: |
            ensemble.storage.userAuthId = event.data.user.id;
            console.log("ensemble.storage.userAuthId");
          onComplete:
            executeActionGroup:
              actions:
                - showToast:
                    message: ${ensemble.storage.userAuthId}

[amin-nas]

@Umair-Manzoor-47 let's rename this to signInWithCustomToken
Also, we need to have the id token available in event.data.user. Since we will be calling secured cloud functions, we need to pass this token in the header. This token should be available for all methods of firebase auth supported by Ensemble.

[Umair-Manzoor-47]

@amin-nas
For clarification
event.data.user must have tokenId sent from backend?
OR UUID that is sent from firebase after user is authenticated and signed in.
Now event.data.user already has UUID.