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.

We add two new arguments to setWallpaperComponentInternal: a callback,
and a boolean to forceRebind. Clearing will call
setWallpaperComponentInternal with forceRebind = true unless we're
clearing FLAG_LOCK only, in which case we just reuse the existing home
wallpaper without rebinding anything.

Flag: lockscreen live wallpaper
Bug: 298366419
Test: atest WallpaperManagerTest
Change-Id: Iba71f250b59b08814033eb9364613c96b15ea966
Merged-In: Iba71f250b59b08814033eb9364613c96b15ea966