The only viable way to remove it is to just swipe the notification away as you would normally do. From what I've seen that usually does it until do not disturb is turned back on. I really hope Apple will add an option to disable this in the future.
Maybe in iOS 12.1 Beta 2.
Seems like it can come back on its own at times even after being dismissed.You can slide the DND notification to the left and clear it, then it doesn't come back.