Reland "use new clearWallpaperLocked method everywhere"

Reland of ag/23728650

The old clear method had a lot of references. Replace these references
with a call to the new clear method. Now, everything that tries to clear
the wallpaper will call setWallpaperComponent(..) and not directly
bindWallpaperComponentLocked.

Flag: lockscreen live wallpaper
Bug: 273443374
Test: atest WallpaperManagerTest
Change-Id: I7c9f9a902d57205b5f54d005c014fdbe00cfc9bd