Make bubble channel setting 3 state with unset / on / off

Test: atest NotificationManagerTest (with CTS cl)
Test: manual - have test app on "all" setting
             - get a bubble
             - hit "unbubble" from notification
             => no longer bubble
             - get update to that notif, it shouldn't bubble
Bug: 154232758
Change-Id: I1611002418cad18ec2426e7d8b4cd4dc93e6df24