By Stephanie Yang, CNN (CNN) — A parade of luxury cars, handbags and yachts up for auction has done little to help their owner, a disgraced Vietnamese tycoon, repay the billions she owes victims in one of the largest fraud cases in history. Once one of Vietnam’s richest businesswomen, Truong My Lan received two life sentences for her central role in a scam where she and her accomplices siphoned about $44 billion through one of the country’s larg…