FRANKFURT (Reuters) -A digital euro could drain up to 700 billion euros ($810.88 billion) in deposits during a run on commercial banks, pushing around a dozen euro zone lenders into a liquidity squeeze, a European Central Bank simulation showed on Friday. The study, requested by European legislators, was aimed at evaluating the risks that a digital currency, essentially an electronic wallet guaranteed by the ECB, would pose to the banking sector under different scenarios, including a hypothetical "flight ...