Refresh cached user array upon lockscreen settings changed

Clear the entire array storing which users allow notifications to
be shown on the lockscreen. This is because we don't know which user
changed the lockscreen settings. Update all notifications afterwards
to fill the array again.

BUG:27118634

Change-Id: Ic4f1a8de75824cd902841867b2a9bf482fd5dd7c
1 file changed