Bill Cosby’s Gilded Age townhouse has dodged foreclosure thanks to a hefty $28 million sale. A buyer snapped up the seven-story Upper East Side home less than a month after Cosby listed it for $29 million , according to records filed with the city Department of Finance on Friday. The final deal, first reported by Realtor.com , closed in early November. The limestone-clad mansion at 18 E. 71st St. sits along one of the city’s wealthiest lanes. It boasts a litany of past and present high-profile