Forget about Sen. Elizabeth Warren. The worst scourge on Wall Street is overly chatty traders. Since 2010, the world’s 13 biggest banks have shelled out more than $74 billion to settle probes, ranging from interest-rate rigging to currency manipulation, where incriminating exchanges between traders provided key evidence, according to a Post analysis of data compiled by the CCP Research Foundation. “Those crimes may not have been possible without electronic communication,” said Brandon Garrett, a professor at the University of Virginia School of Law.