am bbc140b5: Merge "Revert "Revert "Disable setWallpaper button until the wallpaper is loaded" Will submit again after the drop" Actual fix" into ub-launcher3-burnaby

* commit 'bbc140b545ffd6c230269af3b0b5cad98838fc3a':
  Revert "Revert "Disable setWallpaper button until the wallpaper is loaded" Will submit again after the drop" Actual fix