By Daniel Kline Sin City used to be off-limits for professional sports teams, but now it has become a highly desired location. For decades Las Vegas was off-limits for pro sports teams. The city was one of two locations in the U.S., along with Atlantic City that allowed sports betting. That made it dangerous ground for professional athletes who were all apparently a legal betting window away from turning into Pete Rose. Now, of course, sports betting has been legalized in more than half the country (30 states) with more to come. That opened up Las Vegas as a viable location for professional sp…