Don't animate scrim changes to UNLOCKED if we're occluding.

The occlude animation suppresses the notification scrim
alpha to 0f so that the animation can play over the
lockscreen contents. When we finish that animation, we
are currently animating from 1f to 0f, despite the
current alpha being 0f already (due to the suppression).

We can simply not animate this change to fix this, which
is already done for activity launches.

Fixes: 251275444
Test: launch timer from assistant on tablet
Test: atest ScrimControllerTest
Change-Id: Iccbe0124381a6cf1d813e8c1edb6c44b46cbd3fb