Merge "Return empty, not null, a11y node in Workspace" into sc-dev am: 02393204e6

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/13856298

Change-Id: Ib7f3d1a8f30e693297119da1fa57eb7ed6daa2ba