Long-press to configure quick affordances (2/2).

Adds logic to allow quick affordance configuration through a long-press
in the wallpaper picker UI. Also adds such a configuration long-press
for the Do Not Disturbe (DND) affordance.

Fix: 261747112
Test: unit test added
Test: manually verified that long-press on the DND quick affordance
opens the DND settings activity
Test: manually verified that select/unselect all still work

Change-Id: Ic373dcbfbc1e9c742e977347e0f58a82dd0decab