Make FoldableRule more reliable by asserting screen on/off state

After each fold, we now assert that the screen must be off.
After each unfold, the screen must be on.

Bug: 254258287
Test: all android.platform.test.scenario.sysui.foldable
Change-Id: I7981d77d5cda2ab7804634309bd7c2782972e673
2 files changed