After bursting onto the scene as Connell in the hit series “Normal People,” Paul Mescal continues to build a resume that’s going a long way to establish him as a bona fide movie star. His latest outing as a leading man is “God’s Creatures,” a new Irish family drama from Saela Davis and Anna Rose Holmer that promises to be every bit as powerful as their first collaboration, “The Fits.” The film, which follows a dangerous secret that threatens to unravel a family in an Irish fishing town, made a strong debut at the Cannes Film Festival in May.