WallpaperCropper: fix lockscreen wallpaper "Set wallpaper" string

The string is wrong and does not reflect the correct action the user is
about to apply.

Change-Id: I91eba87a38546563d6cf88138a0ed07219ec794f
Signed-off-by: Roman Birg <roman@cyngn.com>
Move 3rd party wallpaper pickers to the front

This is a feature request from Steve so here you go!

Change-Id: Iac6a26c7b51752d65026a871712c3590caa926d9