Support direct calls to go away

This can happen in the case of activities requesting dismissal
over an unlocked lockscreen. Detect this case and allow the
exit animation to proceed.

Fixes: 436308551
Test: atest KeyguardViewMediatorTest
Flag: EXEMPT bugfix
Change-Id: I9b8fa6a8f6b227779d2f539b6c918b4133bbb52f