Fix WallpaperDescription Parcel/XML encoding error

This issue causes crop hints passed to one WallpaperManager.setBitmap
method to be ignored, which in turn caused a GTS test failure.

Fixes: 417757911
Fixes: 422842228
Flag: EXEMPT bugfix
Test: GTS test passes
Test: updated FrameworksCoreTests
Change-Id: I7ff1c1a89a81de9c629ffa62cb56bd6faf914af1