fix: close preferences when going to background

Whenever we go to background and preferences are open, close
the preferences view before. This avoids the annoying situation
where ring is in preview mode and the camera continues recording
the user.

Change-Id: I10bcb2f8b46c5750757763913fcd6b0e1e635302
Tuleap: #1851
Reviewed-by: Sébastien Blin <sebastien.blin@savoirfairelinux.com>
3 files changed