Merge "[Status Bar Refactor] 3/N: Move PanelBar#onPanelExpansionChanged into PanelExpansionStateManager." into sc-v2-dev am: 19444c3a47

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/16102500

Change-Id: Ib894a517c659887457a3dd82e366a491e695f2e4