Use new OverlayManager categories

Using this, we split overlays based on their category, so that
cutout emulation and theme overlays no longer clash in their
respective settings.

Bug: 72436677
Test: make ROBOTEST_FILTER=EmulateDisplayCutoutPreferenceControllerTest RunSettingsRoboTests
Change-Id: I23f22113351b3948beb9e3a1fb969700852539cc