Music Review: Charli XCX's 'Brat' swings between hedonism and anxiety, cult classic and pop party

English pop singer-songwriter Charli XCX 's sixth album, “Brat,” oscillates between hedonism and anxiety — the euphoria of a late night on the dancefloor and the creeping disquietude of the morning after — as much as it does her in-between status as pop queen of the underground and...