Use non-deprecated method to check shade expansion.

Some combination of UMO, shade expansion, and lock/unlock can get us into a state where isPanelExpanded returns the inverse value of actual shade expansion. This results in us controlling the screen off animation when we're not expecting to, resulting in unpredictable jank as well as unlocked app content remaining visible at unexpected times during the screen off animation.

I don't know why this happens, but that method is deprecated, and updateControlScreenOff() is initially triggered by the SbStateController mIsExpanded updating, so we should just query that value for consistency.

Fixes: 437490510
Test: manual, I figured out how to repro sometimes and confirmed that reaching that same state with this fix fixes it
Flag: EXEMPT bugfix
Change-Id: Ic31e5c14fe371370c67b4b12c31ac62eb40dd32f