Merge "Do preview grid migration in a worker thread am: 6b79a3767d am: f1c369589a am: 5dc6bbc830" into rvc-qpr-dev-plus-aosp am: 5e37afd503

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

Change-Id: I8663db7a03cd908cf4d9ecda9d22b934b1389e44