Add step slider for presets

Add a step slider for clock presets. This is only handling showing and
hiding the slider when choosing different clock styles.

Test: Maually tested. See bug.
Bug: 395647577
Flag: com.android.systemui.shared.new_customization_picker_ui
Change-Id: I47753873a13c1dddfaf4bd2d4b367a2f91dbd917