[Android] You are wrongly redirected to the "Cannot create account" screen on each sign in attempt after entering an invalid age and waiting 30 seconds before closing the app

[Softvision-MariusComan]

[Affected Platforms]:

• Android 8.0.0 (Google Pixel)
• Android 8.0.0 (Samsung S8)
• Android 6.0 (Huawei P8 Lite)

[Prerequisites]:

• Have the latest version of the "Firefox Notes" application (app-release-signed) custom built on 7/31/2018 installed.
• You are not logged into "Firefox Notes".
• Have an email that is not linked to "Firefox Account".

[Steps to reproduce]:

1. Open the Notes application and tap the "Sign In" button.
2. Enter the email from prerequisites and tap the "Continue" button.
3. Write and confirm a valid password.
4. Enter an invalid value in the "Age" field and tap the "Create account".
5. Wait ~30 seconds and fully close the app.
6. Reopen the app and tap the "Sign In" button.
7. Observe the behavior.

[Expected result]:

• You are redirected to the email screen.

[Actual result]:

• You are redirected to the "Cannot create account" screen.

[Notes]:

• This issue is also reproducible if the app is in the background or if the phone is locked.
• This issue is still reproducible if the app is forced closed.
• This issue is no longer reproducible after the app's data is cleared.
• Attached a screen recording of the issue: