An animated adventure for all ages, with original music and an all-star cast, “Smallfoot” turns a myth upside down when a bright young yeti finds something he thought didn’t exist—a human. News of this “smallfoot” throws the simple yeti community into an uproar over what else might be out there in the big world beyond their snowy village, in an all new story about friendship, courage and the joy of discovery.   “Smallfoot” stars Channing Tatum (“The LEGO® Batman Movie,” the “Jump Street” films) as the yeti, Migo, and James Corden (“Trolls,” “The Emoji Movie”) as the Smallfoot, Percy. Also starring are Zendaya (“Spider-Man: Homecoming”), Common (“Selma”), LeBron James…