By Daniel Kline MGM, Caesars, and Wynn prepare for the fallout of a new Sin City Marijuana law. Las Vegas (and the entire state of Nevada) have legalized marijuana, but have not made it easy to actually smoke it for tourists. That’s because while dispensaries like Planet 13 (PLNHF) operate legally, they’re not allowed to have on-site consumption lounges. In addition, hotels, including the massive casinos operated on the Las Vegas Strip by Caesars Entertainment (CZR) – Get Caesars Entertainment Inc Report, MGM Resorts International (MGM) – Get MGM Resorts International Report, and Wynn (WYNN) -…