Add VolumeDialogSliderTrack to support animated icons at the end of the

track.

Flag: com.android.systemui.volume_redesign
Bug: 369994956
Test: atest VolumeDialogScreenshotTest
Test: manual on the phone. Check slider adjustements and overscroll
animations

Change-Id: I8ded71ea19ff95295a18b933b2355679263e9ecf