MADISON, Wis. — The Wisconsin State Assembly Republican leader who hired a former state Supreme Court justice to investigate the 2020 election fired him Friday, three days after the lawmaker beat a primary opponent whom the investigator and former President Donald Trump had endorsed.The firing of Michael Gableman capped a 14-month ride that began when Assembly Speaker Robin Vos hired him to look into the election under pressure from Trump. But as the probe progressed under bipartisan criticism, Vos&rsquo …