QS + DND interaction again

 - Fix up attach/detach because those aren't good signals for DND
   panels, instead use aggregate visibility
 - Do better initialization on open because filling in that state
   is now important (previously it was guaranteed to be just turned
   on)
 - Fix when forever is selected, if DND is on and doesn't have a
   condition, it doesn't mean we should turn one on.

Test: manual
Change-Id: I61dcf3c2b17179b5867f017c767d0c2d6d4940f3
Fixes: 37366004