Keeping the lockdown state in sync with the notification list

Whenever the lockdown was changed, the UI wasn't consistently
updated, but only once another notification / update came
in, which lead to notifications being invisisible or visible
when they shouldn't have been.

Change-Id: I17c1b4e0ef58d6aa05f4404e52e07a098d4fce4e
Fixes: 78020486
Test: manual, hit lockdown observe notification gone, coming back when unlocked
(cherry picked from commit ddb7b47d)