Ensure that we always have a useable wallpaper token for animation

Bug: b/347593088
Test: presubmits
Flag: NONE minor refactor
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:6d6cab2e9a0b923ad4c54a7b77e41d45fc8d9804)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:0ea8d6f2b5c54bdcf3aebeb0aa70bd3e10f05169)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:9dea1fabbe98913024786baf878df64c2e572168)
Merged-In: Ia971daa962beab3fd4c93215b480280a9384b380
Change-Id: Ia971daa962beab3fd4c93215b480280a9384b380