Remove legacy exit animation condition

This path is no longer needed and obsoleted by remote
animations. It also makes a race condition worse, when
an occluding app is launched just prior to keyguard
becoming visible.

Fixes: 329587571
Test: atest KeyguardTests:testTranslucentShowWhenLockedActivity
Flag: N/A
Change-Id: I26664694568d9fdf401ca14919c31dce4bb92628