Focus Assist is my default. Always.
I'm trying to reduce the notifications in the Action Center to the minimum possible.
How can I remove this notification for good:
To clarify, I want Focus Assist to be always on. I don't need THIS notification to tell me that.
I'm good with the little 
icon to tell me that. Hence I want the notification saying "Your notifications will remain quite here..." removed, while Focus Assist is on.
