If you were hoping to get your hands on one of the pambazo sandwiches at Mexcla (2818 Cherokee Street; 314-449-1220), you're out of luck. After just one month, the restaurant appears to have closed.Mexcla, which opened in late May on Cherokee Street in the former Tarahumara space, has been dark for the last two weeks, according to neighbors who asked not to be named.…