Ariana Grande and Cynthia Erivo have been around the world promoting their new movie ... and now they're back stateside for one last rodeo. Ariana and Cynthia were in lockstep Monday at the premiere of "Wicked: For Good" at the Lincoln Center in New York City. The cast previously hit premieres in Brazil and Singapore, where things got dramatic when an unruly fan jumped a barricade and attacked Ariana. Cynthia rushed in to help , acting as Ariana's bodyguard ... and the guy has since been