[auth] Auth lockscreen fixes

[AmanRajSinghMourya]

Description

1. Removed the logout button from the lockscreen if app in without backup state
2. Show a warning dialog when user try to set the app lock for the 1st time

Tests

[ashilkn]

@AmanRajSinghMourya Can change the copy to "You have chosen to proceed without backups. If you forget your applock, you will be locked out from accessing your data."

[ashilkn]

Names aren't used coherently. getOfflineModeWarningStatus returns a bool but isn't clear how the status and boolean returns are related.

getOfflineModeWarningStatus returns the key ls_show_offline_mode_warning. So it's expected if getOfflineModeWarningStatus returns false, we should not show the warning. But the use of getOfflineModeWarningStatus here isn't following that expectation.