Add new AppOp for SYSTEM_APPLICATION_OVERLAY

During special, privileged MediaProjection sessions the recording app
may add system application overlays.

MediaProjectionManagerService manages the AppOp state,
WindowState enforces on system server side.

Bug: 395054309
Flag: com.android.media.projection.flags.recording_overlay
Test: atest MediaProjectionManagerServiceTest WindowManagerServiceTests
Change-Id: Id431608ab0c6e774e2faf34b05b1b63d9fa9ae21