Fixed a crash when a notification is updated

Under certain conditions, the minheight could be
queried while reset or when an inflation error happened
for an existing notification.
Since all notifications have collapsed layout anyway
that will always be set after reset, we don't have
to null those out.

Test: click clear all, have first notification update during the animation.
Bug: 32333389
Fixes: 33961825
Change-Id: I14a75cd628726c8acd892a81b95de40f92275bb1