Merge "Implement the custom style flow part 2" into ub-launcher3-master am: f619e598f7 am: 81fdd9b54e

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/ThemePicker/+/11683414

Change-Id: I6ae047bd4b90bf4599a56c1f6b23714cfcd80e84