LOS ANGELES — Zendaya, clad in a skintight dress, gyrates on a dance floor in “Challengers,” a $56 million sports drama that arrived in multiplexes Friday. “It’s getting hot in here,” the hip-hop soundtrack intones, as she closes her eyes and runs her hands through her hair, lost in fantasy. “So take off all your clothes.” The story continues at a motel, where Zendaya, playing a tennis prodigy, begins a menage a trois with two guys; it fizzles after they become more interested in each other. The