Merge "Show an empty view when there is no widget available" into sc-dev am: a061cf3387

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/13819245

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: If63f5669d913b06f63aac302268a7c1e708b019b