Merge "Do preview grid migration in a worker thread am: 6b79a376 am:...

Merge "Do preview grid migration in a worker thread am: 6b79a376 am: f1c36958 am: 5dc6bbc8" into rvc-qpr-dev-plus-aosp am: 5e37afd5

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/12002728

Change-Id: I8663db7a03cd908cf4d9ecda9d22b934b1389e44