No. Because Combat Celebrant only cares whether or not it has been exerted this turn. Not whether or not it is or isn't tapped. So when you go to use it's ability the second time around it checks, has it been exerted already this turn? The answer is yes so the ability can't trigger again.
February 10, 2019 8:28 p.m.
Aurelia, the Warleader + Helm of the Host does go infinite though. This is because every time you go to combat you create a token, and since that token is attacking for the first time you get another combat. Basically you then just beat everybody up with giant flying Angels.