Most of the excitement, such as it was, about last night’s poorly-attended match between the Washington Kastles and St. Louis Aces vanished when the main attraction, former star Anna Kournikova, was sidelined by a wrist injury. Or, at least, that would be true if the WTT was really about tennis, which it is not. Party tennis is right: the tour is obviously more entertainment than sport, focused on giving away T-shirts and Chipotle gift certificates…