Rihanna once again rolled up to the Met Gala fashionably late — and as usual, it was worth the wait. The superstar hit the iconic red carpet over an hour after the rest of the A-list guests had gone inside on Monday — and after the Vogue livestream had already come to an end — this year wrapped in a glittering gold and silver Maison Margiela gown, with her hair also featuring golden spirals. She walked arm-in-arm with partner A$AP Rocky , who rocked a pink robe over his tux. Rihanna has become one of the most highly anticipated Met Gala guests throughout the years, consistently breaking the internet with her looks — and last year revealing her third pregnancy on the Met steps.…