Merge "Removed onBackPressed handling in SplitSCreenSelectState" into sc-v2-dev am: e7e3d6ad31

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/16371718

Change-Id: Ic18862107a5bcfb1f8f7fa9ad3c525fff841f36a