Legal tech startup Harvey this year has bagged $760 million in funding and soared to a valuation of $8 billion. Now it needs to prove that it can actually boost profits for the law firms that pay for its services. Harvey, which on Thursday announced the close of a $160 million funding round, says its products free lawyers from drudge work so they can spend more time on strategy and client counseling. But at this point, Harvey's ROI shows up in feelings more than spreadsheets. Law firms want the