Update the reorder function to also support adding item during reorder.

- Dao class today accepts a priority when adding widget, so on the same
lines updated the updateOrder function to accept mapping of widget ids
to priorities.
- By accepting priorities, it also makes the input ordering more
explicit (instead of ordered list)
- Updated tests to also test for "order" using `.inOrder()`

Test: atest CommunalWidgetDaoTest
Bug: 315209740
Flag: ACONFIG com.android.systemui.communal_hub DEVELOPMENT

Change-Id: I594afb33a61c49f6bba3307c21f16a3506d07c3c