Update preferences to rely on CarUiRecyclerView to provide dividers

Dividers for preferences will now be controlled by the divider
configured for CarUiRecyclerView. OEMs can remove the divider by setting
car_ui_recyclerview_divider to null.

Bug: 146163670
Test: Manual

Change-Id: I609bf73b82c6d12300be06b496dcd3431d7a3e5e
2 files changed