I agree that he’s probably happy with this incident (given that he only recieved a minor wound, that will probably be very visible whenever he’s infront of a camera. But his reaction of calling “fight” is prefectly in line with him being a very defiant person, who’s also very politically savvy. It was a perfect response, if you want people to think all political opponents are the enemy.
And Trump also don’t lack for “courage”, if you can call an egomaniacs conviction that everything will always go his way that. I don’t see anything strange with it, given his character.