Start unfold Shell transition from WM side only when unfolding

Changes the conditions when we start the unfold
shell transition only when we switch from folded
state to unfolded or half folded.

This fixes an issue when we start the transition
e.g. in rear display device state where
physical display switch happens but we don't
play unfold transition. As we don't play the
transition, the UnfoldTransitionHandler never
finished it which led to 5 seconds of
a frozen screen.

Test: atest WmTests:PhysicalDisplaySwitchTransitionLauncherTest
Test: manual fold/unfold
Bug: 275343878
Change-Id: Iad0c2d62da8fa5d6205f57ffc100e83e92715ac2