Fix manual brightness slider

Pending brightness change never stored
in current brightness.

Bug: 72725570
Test: manual - non-adaptive move slider check it works, reboot check brightness was persisted.
Test: manual - adaptive - move slider check it works.
Test: manual - verify slider events are logged for adaptive and not for manual brightness

Change-Id: If2914dcb223cf4308f178c101e862e6b4ba851bb