Improve animation from keyguard shortcut

This CL improves the activity launch animations from keyguard shortcuts
by changing their background to be a rounded rectangle instead of an
oval, so that it can be properly animated during the launch, and by
adding support for StateListDrawable in
GhostedViewLaunchAnimatorController.

See b/265280100#comment6 for a video.

Bug: 265280100
Test: Launch an activity from a keyguard shortcut
Change-Id: Id22045a64a062ebea5be5adebda667f4616f0597