Merge "Fix NPE when converting final screen to empty screen." into sc-qpr1-dev am: 70dd01be85 am: 46db057249

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/15583988

Change-Id: I1ad5dc4cc140498529b940b35a1b40988a3e1946