A federal judge gave a transgender performance artist the go-ahead to challenge a Chicago ordinance that bars women — but not men — from exposing their breasts in certain venues.In a written opinion this week, U.S. District Judge Andrea R. Wood did not rule on the merits of the arguments Bea Sullivan-Knoff raised against the city’s prohibition on nude and semi-nude performances in establishments licensed to sell liquor.But Wood held Sullivan-Knoff is entitled to pursue several of the claims she brought …