Merge "Remove stage concept from split screen APIs" into tm-qpr-dev am: 6aca959b am: 080a4f5c

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/20111332



Change-Id: Ia7a1cb479873a7a4563204b21af1a38b9b1d39b9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>