Remove obsolete wallpapers from core product mks.

These packages were removed from a standard checkout in
I7db6b9fbe13d65e717d99d6ee44dd78c8804b05c, and are unlikely
to be used in any other manifests. They were probably just
left here by mistake. Remove them from the core product mks.

Note that the repositories still exist, but they appear to
be abandoned:
https://android.googlesource.com/platform/packages/wallpapers/

Bug: 111729974
Bug: 80410283
Test: make
Change-Id: I3fb2dad49f4f0dd571f73202747f49fcde0563ff