Scale wallpaper preview surface instead of preview image am: 8557c46d85

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/WallpaperPicker2/+/13178976

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I4debcf4e760eb4cc915a4d4fdf61c17394ec88f5