Revert "Revert "Notify display brightness changed due to brightness transforms""

This reverts commit fed3221c90441289af64108a25432353f6bb8cf9.

The original revert (the commit above) fixed a regression. That
regression has now been root caused and fixed in a preceding commit
(ag/16693523).
The original revert is now no longer required.

Bug: 202873446
Test: Manual, sliding the brightness slider around and ensuring it stays
    in place after the user lets go of it.
Test: atest QuickQSBrightnessControllerTest BrightnessSliderTest
Change-Id: I3d1b674fe11706accd1cad1578f1861bdf513737
1 file changed