Update lockscreen workspace of live wallpaper full preview to vary against wallpaper color

Launcher: https://screenshot.googleplex.com/jG2tXeDDJsN.png
Small preview: https://screenshot.googleplex.com/bywtiEqjE52.png
Live wallpaper full preview:
- Before: https://screenshot.googleplex.com/9ddbFEXMrWM.png
- After: https://screenshot.googleplex.com/ESsM8744sKA.png

Test: Manually
Bug: 159195012
Change-Id: Ic25234c4647053c1882bd711b76fb75b96034fef
1 file changed