DALLAS — The Mavericks appeared primed to cruise to an easy victory Thursday night over the travel-weary New Orleans Pelicans — until Luka Doncic tried to dunk. About five minutes into the third quarter of Dallas’ 111-106 win, Doncic drove toward the basket and looked to score over Pelicans center Jonas Valanciunas. But when he took off, lifting the ball with his left hand, Pelicans star Brandon…