Disney has made big business mining content from content, with spinoffs and sequels and multiverses dancing through multiplexes and streaming apps. “Lightyear,” the latest Disney/Pixar animated film, has been extracted from the much-beloved “Toy Story” universe, but it’s a bit unique. It’s sort of a prequel, in that it’s intended to be Andy’s favorite movie, the one that spawned the Buzz Lightyear toy that took up residence in his room with Woody and the rest of his pals. So “Lightyear” is not about Buzz Lightyear, the toy, but about Buzz Lightyear, the character, and this satisfying animated …