lockScreen: Don't wake up screen in DND mode

Screen woke up whenever a new notification popped up
on lock screen even when DND was turned on.
This commit changes this behaviour to not wake
the screen up in such case.

https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/4710

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2051>
(cherry picked from commit 92071400)