Merge "Show back button in SUW" into sc-v2-dev am: 64af7acc1d am: 23a7c3cd0b

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/15687150

Change-Id: I3b5e86227fb54e302f5ebaf7ab1d86720d418385