Ensure reordering of notifications is allowed when communal is showing.

When on the hub, we should still allow notification reordering - as
notifications are hidden but can still be accessible via the shade.

Bug: 330532773
Test: dumpsysui VisualStabilityCoordinator
Test: atest VisualStabilityCoordinatorTest
Flag: ACONFIG com.android.systemui.communal_hub TEAMFOOD
Change-Id: I8a5b20feff062f4176cdc3927858d3f167a5d239