Only send brightnessChangeEvent if display is on

Here, we add a check to ensure that the dpc that is sending the
brightness change event only if autobrightness is enabled on that dpc.

Bug: 280531558
Test: atest android.display.cts
Test: atest com.android.server.display
Change-Id: Idc089e2c97d8c47e3251c5cbd85a14919d6454cc
4 files changed