DO NOT MERGE: Add SystemUI support for front-facing camera protection

Devices with a DisplayCutout configured may want to add some extra area
of turned-off pixels around the cutout in order to keep light from
leaking into camera hardware. This CL adds two new config values to
sysui to enable the configuration of this cutout protection, and listens
for CameraManager events telling us that a relevant camera has turned
on.

Test: manual
Bug: 145095085
Change-Id: Ifce67a593247e3a2151d41800ae46a50478e0b7d