Stephen Sondheim’s musical about the long, complicated friendships of a trio of creatives, which was savaged by critics when it first debuted in 1981, has been rethought and restaged in an acclaimed revival that is now back on Broadway. Correspondent Rita Braver talks with stars Daniel Radcliffe, Jonathan Groff and Lindsay Mendez, and director Maria Friedman, about bringing a work by one of the greats of musical theater to new light.