This might be the most Mariah Carey moment ever. The elusive chanteuse was out and about in New York City on Sunday and pulled the diva card when asked who is qualified to sing at her upcoming wedding to billionaire fiancé James Packer. Mariah is truly the only person who could get away with an answer like this. Her dream wedding singer? “F**king nobody. Bye!” she declared. ET caught up with the 46-year-old songstress at the NBC Universal Upfronts on Monday, where Mariah, who donned a sequined tiger-striped minidress and fishnets, delivered even more diva antics and confirmed she is so not a morning person. “I know it’s not morning…