Delay possible re-entrant call to updateNotificationViews()

NVHM.onDynamicPrivacyChanged() both calls updateNotificationViews() and
could be called by updateNotificationViews(), resulting in very-bad,
no-good re-entrant behavior. It's too late to try to rearchitect the
entire shade to avoid this relationship, so instead we delay a frame
before applying the update.

Bug: 135018709
Test: atest, manual
Change-Id: I0b17d5ba16e272015b10be182a07cae6b29270e6