base: display live wallpaper settings instead of wallpaper picker

If the livewallpaper service declares and supports a settings activity, display it
instead of the wallparper picker in runnings apps details settings activity
(settings button)

Change-Id: I8db800cec4151ee5e6edddcea7a1bb5fb0528816
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>