Fix some B&R gaps

1) we weren't storing 'has sent valid bubble', even on reboot
2) we weren't backing up 'hide silent status bar' for secondary users,
but we need to in case the user is restored as a primary user

Test: PreferencesHelperTest
Fixes: 303169453
Change-Id: Ie77f1eeb48072c7af65d6c1cf33d729f6344587e