Do not show/ring call notification when user status is DND

[tobiasKaminsky]

• enable DND, either on server or within Desktop client
• receive an incoming Talk call

--> do not have the call sound/notification window

[mgallien]

would need something like #4507

[nickvergessen]

Sounds related yeah. Not sure it's fixed already, just had the embarrassing moment yesterday with a customer while being on Mac, no update available