Align bubble behavior with DND settings.

As described at https://docs.google.com/presentation/d/1mPxqu8QBWpz-ieWkJGyLzBLcfAJNVUn8sxS1m58ogn8/edit#slide=id.g51f96ac1fd_25_230.

Due to b/132699005, the 'new' dot won't appear if 'Don't pop notifications on screen' is selected in DND restrictions.

Test: atest SystemUITests
Bug: 123540994
Fixes: 123540994
Change-Id: I38958555721fa3d9dd44c451c32c28d9a73415f5