Delete ShadeTransitionController

ShadeTransitionController and ScrimShadeTransitionController don't seem
to do anything but listen to ShadeExpansionStateManager and pass some
of its data to ScrimController, so this change deletes one of them and
corrects how the other is initialized.

Flag: N/A
Test: Updated and ran affected tests
Test: Manual
Bug: 303267342
Change-Id: I5bba929869dfe025bdc2f44c0f2cc5956cdd7c0b