WASHINGTON — The 1/6 committee is set to plunge into Donald Trump’s last-ditch effort to salvage the 2020 election by pressuring Vice President Mike Pence to defy historical precedent and reject the electoral count in the run-up to the U.S. Capitol riot.With two witnesses Thursday, the House panel intends to show how Trump’s false claims of a fraudulent election left him grasping for alternatives as courts turned back dozens of lawsuits challenging the vote.Trump latched onto conservative law professor …