Fix: back button press on signin/signup page

[kefeh]

Version Information

Device	Value(s)
Device type	Pixel 7
OS version	Android
installed package version

Description When on the registration screen, clicking the phone back button takes you to a grey blank screen with a circular progress indicator

Steps To Reproduce

1. Sign out of the app or run the app
2. complete the onboarding and enter the registration page
3. press the default phone back button

Expected Behavior should not show the screen

Screenshots If applicable, add screenshots to help explain your problem.

Additional Context

https://user-images.githubusercontent.com/15707199/222367696-c4bfdedd-07e9-46bb-8138-d55f54cd813b.mp4

Possible Solution Should either a.) provide a prompt asking the user if they are sure they want to quit the app and suggest to press the back button again to quit or b.) just quit the app