[FxA] The app crashes if the account is reconnected from the same "Sign in" page accessed by clicking the "Back" button

[Softvision-RemusDranca]

[Affected Versions]:

• Firefox Reality version 11 RC6 (e4f476e).

[Affected Platforms]:

• Oculus Quest - Android 7.1.1
• HTC Vive Focus - Android 7.1.2
• Pico Neo2 - Android 8.1.0

[Prerequisites]:

• The Firefox Reality browser is open.
• Have a valid FxA account.

[Steps to reproduce]:

1. Log into the FxA account using your email and password.
2. Sign out from the FxA account.
3. Click the "Back" navigation button to open the "Log in" page.
4. Enter the password and click the "Log In" button.
5. Observe the behavior.

[Expected results]:

• The page can't be accessed by navigating back or an error is displayed.

[Actual results]:

• The app crashes.

[Notes]:

• If Step 2 is not performed, the Log In page remains in a working (loading) state.
• It seems that the "Back" button is only actionable when login into the account through both FxA Log in pages (Email and Password).
• I marked this issue as a regression because on RC2 v11, the'Back" button was not actionable after completing the login process.
• Attached is a screen recording, logcat and the crash report of the issue:
  • Screen Recording: link.
  • Crash Report: link.
  • Logcat: link.

[Softvision-RemusDranca]

I have verified this issue and it's no longer reproducible with Firefox Reality version 11 RC8 (076802a). Now, the same "Sign in" page can't accessed by clicking the "Back" button.

Tested on Oculus Quest (Android 7.1.1), HTC Vive Focus (Android 7.1.2) and Pico Neo2 - Android 8.1.0.