Merge "Fix the custom theme page shape bug" into ub-launcher3-master am: 77140557c6 am: d5f8377f88

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/ThemePicker/+/11570142

Change-Id: I33fa1d44b08b73db3b4ae4bbf5320b88f17ec892