“Maybe I should go see it with my lawyer,” Diana Ross once said of “Dreamgirls.”Scarlett Johansson in 2025; Diana Ross, circa 1967; Justin Baldoni in 2024Credit: Kevin Mazur/Getty; Michael Ochs Archives/Getty; Araya Doheny/Variety via GettyArt imitates life imitates...In summer 2026, word started to spread that the movie star at the center of Rachel Cusk’s new novel, Life of M, appeared to draw heavily from the life and career of Natalie Portman…