Additional polish for the NORMAL<->ALL_APPS transitions.

The depth of ALL_APPS is set to 2 because in the legacy transitions the
swap happens at 0.5. The depth controller bounds the value to 1, so for
the second half of the animation the value is always 1. Because of this,
in order to have the right timing during the blur and scale we cap the
interpolator to 0.5.

Workspace fade is also removed, per spec.

Bug: 232418544
Test: manual
Change-Id: Idfd92c8b2b571ad911a0a5a59d39c5911e4131e4