Play notification sound regardless of "do not disturb" about time-limit

[marbetschar]

The suggested approach for this is to set the notification's priority to NotificationPriority.URGENT which essentially bypasses do-not-disturb.

However, this does not work as for the currently used gala notification server in elementary Hera 5.1. We need to test, if this works as intended on the new Gtk notification server for Pantheon by building it from master and then set /org/pantheon/desktop/gala/behavior/use-new-notifications to true.

To do so we use gsettings in Terminal or dconf. For terminal:

gsettings set org.pantheon.desktop.gala.behavior use-new-notifications true

PLEASE NOTE:* At the time of this writing you need to compile and install gala as well as the new notification server from master branch. Both are not officially released yet.

[marbetschar]

Blocked by: elementary/switchboard-plug-notifications#29

[marbetschar]

Added "Bypass Do Not Disturb" PR: elementary/switchboard-plug-notifications#84