Sam Elliott isn’t allowed to act anymore. He can’t show up as a stunt-casting gimmick on “Will and Grace,” or in some throwaway action flick. He can’t even voice-over a barbecue sauce commercial. No, he made “The Hero” (2017), which is one of those magnum-opus-type star turns that aging actors suddenly summon when they still haven’t won a major award. Sam plays a pot-smoking actor who made a great cowboy film long ago, but he’s dying now, and he’s trying to figure out how to die, and still live, and it’s pretty impressive. So no more acting, Sam. We’re good.