Update 'dnd is hiding notifications' view

Add an icon and alawys show the view if DND is on and suppressing
notifications from the shade. 'Manage notifications',
'no notifications', and 'clear all'are hidden when this view is visible.

Bug: 78586809
Test: atest SystemUITests
Change-Id: I9d68fda8a3bc3213c20f9e57ca64d75eebdc1d94