Adding haptics to Brightness slider in Compose.

This change integrates the SliderHapticsViewModel into the
BrightnessSlider composable, bring it up to par with the current state
of haptics in this control.

Test: manual. Verified haptics are working correctly while dragging.
Test: presubmit.
Flag: com.android.systemui.haptics_for_compose_sliders
Bug: 341968766
Change-Id: Iac93ecfbb0ec62243563f30da2f8058ea2969b64