Dua Lipa had all that Mermaid Barbie training.The Grammy-winning songstress — who had a tail of a cameo in last summer’s “Barbie” blockbuster —needed all of her water-nymph powers as she presided over a rain-soaked Times Square on Sunday night in a surprise pop-up performance that still had fans braving the elements to dance the night away.It completed the Dua Lipa NYC takeover this weekend to launch her third album, “Radical Optimism,” which included her serving as host and musical guest on “Saturday Night Live.”And certainly, some “Radical Optimism” was needed to brighten up a cold, soggy Cinco de Mayo that felt more like Cinco de Marzo.Even the diva’s dad, Dukagjin Lipa, knew it — the former Kosovan crooner handed out $2 bills for good luck to guests as he was entering the VIP area.“New York!” the British-Albanian singer exclaimed as she took the stage inside of a trailer parked at the corner of 43rd Street and Seventh Avenue.Flipping her burgundy-tinted tresses like the former model she is — while safely covered from any hair-busting bursts from the skies — she launched into “Training Season” like a well-conditioned pro as her mammoth likeness took over the Nasdaq and Amex jumbotrons.Welcome to Dua Square.It was certainly a feat to get the crowd — which stretched all the way to 47th Street — levitating to any degree.“Thank you for braving the rain and the cold,” Lipa, 28, said.And for her next trick, Lipa performed “Houdini” — the first single from “Radical Optimism” — which possesses the same kind of dance-pop magic she has been crafting since her 2017 breakout hit “New Rules.”Then Lipa shifted into midtempo mode for the “Radical Optimism” closer “Happy for You,” which seems determined to prove that she can do more
