Factor out explicit animation types for the stash/unstash animations.

This consolidates the logic on what animation to play into one place, and will simplify tuning the lock/unlock transitions

Bug: 275319714
Test: manually (http://shortn/_Q1dTzmIpqK), unit tests
Change-Id: I9ba9c9f13dbbff88d8515e567fdb3dfe5556553e
1 file changed