Restoring SDR brightness immediately when entering dim state if the

device is in HDR brightness scale mode.

Because the mBrightnessReason.modifier is updated after scaling HDR
brightness by calling mHbmController.getHdrBrightnessValue(), so
if the device is entering dim state, the brightness will still
scaling to HDR brightness, instead of setting to dim brightness
directly.

Bug: 274763122

Test: atest BrightnessThrottlerTest DisplayModeDirectorTest BrightnessLevelPreferenceControllerTest HighBrightnessModeControllerTest
Test: Manually operations:
1. Enable HBM function;
2. Open a HDR layer;
3. Wait until the screen is dimming;
4. Check related logs.

Change-Id: Ie8ba03cfdd4a8aa446071e05db1c302182a92939