Mentorship-android: Log out feature keeps the back navigation bug

[isabelcosta]

Describe the bug

When I logout the app I got to Login Screen and if I then click the back button, I'll go to the Main Screen, which requires authentication. Requests following this event, give a "Authorization Token missing" which is normal because the logout feature deletes the token locally.

To Reproduce
Steps to reproduce the behavior:

1. Go to "Settings" while logged in
2. Click on "Logout"
3. Click native back button
4. See the Authenticated screen
5. Go to a Members screen, and you'll see the request error "Authorization Token missing"

Expected behavior

Back button should close the app.
Navigation history shold be "cleaned" when logging out.

Screenshots

Additional context
None

[shiv07tiwari]

@isabelcosta Can I work on this ?

[isabelcosta]

Hey, @shiv07tiwari yes you can :)

I see you already sent a PR, and I will review it once I get a chance. But be aware that we ask of contributors to ask first, then when the maintainers approve that you work on it, you can send the PR. This helps us manage the issues, and confirm that the issue is still valid for you to work on. Here's a guide on getting started here.

[shiv07tiwari]

Okay sure I will remember it. Sorry !

[isabelcosta]

Great @shiv07tiwari ! No need to apologize :)