WASHINGTON — Recently retired Supreme Court Justice Stephen Breyer has become the honorary co-chairman of a nonpartisan group devoted to education about the Constitution, joining Justice Neil Gorsuch at a time of intense political polarization and rising skepticism about the court’s independence.The National Constitution Center in Philadelphia said Thursday that Breyer and Gorsuch, who has served since 2019, will be spokesmen for civics education and civility in politics.The justices’ decision to work …