Brigid Berlin, a fixture of the downtown art world in the ’60s and ’70s, will be forever associated with Andy Warhol — the Factory superstar played Duchess, a version of herself as a lesbian drug dealer, in Warhol and Paul Morrissey’s 1966 film “Chelsea Girls” — but three years after her death in 2020, a new exhibition considers Berlin’s art in its own right. “Brigid really was an innovator when you think of the way she used persona as a medium,” says Alison M. Gingeras, who has curated “Brigid Berlin: The Heaviest,” at New York’s Vito Schnabel Gallery, which examines the artist’s life, from her tony uptown upbringing to her secluded later life, with the wild times in between.