Make WallpaperMS bind wallpaper component PendingIntent immutable. am:...

Make WallpaperMS bind wallpaper component PendingIntent immutable. am: b3929030 am: f75396d3 am: 286aa8b9 am: 7e53b789 am: 7e24456d am: c201373d am: 46bdd4af am: 5d676077

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/12718696

Change-Id: I706d3002c96cdb55e48fb2fc31334d7a352859e3