QS in split shade should listen to changes earlier

This makes QS listen to changes and update itself immediately when expansion starts, compared to current state when state is updated only after full expansion is finished.

Bug: 253162395
Test: QSFragmentTest
Test: go to settings -> change brightness -> expand split shade and see brightness is updated immediately, before shade is fully expanded
Change-Id: If1fb81ed3a0d0963fde83e95650c2b3b7663562c