Debug hook for changing display brightness

adb command that allows the AOD brightness to be changed:
adb shell am broadcast -p com.android.systemui
-a com.android.systemui.doze.AOD_BRIGHTNESS
--ei brightness_bucket {BUCKET_HERE}

Fixes: 116060647
Test: adb shell am broadcast -p com.android.systemui -a com.android.systemui.doze.AOD_BRIGHTNESS --ei brightness_bucket 2
Test: atest DozeScreenBrightnessTest
Change-Id: I57de0801aac17a3df466899aec2cf4f37a017d33