Merge "Remove stage type from split screen APIs" into sc-v2-dev am: 36eb818600 am: b1b74d4f63

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/16362386

Change-Id: Idbdf735630347e8b181cf567f58dc2ab1f92cca5