It’s an animated offering with a lot of names in the cast and an untested studio behind it. L. Frank Baum’s books are in the public domain, and animation is still the most consistently lucrative corner of the business (expensive, too) to break into.Lea Michelle, Bernadette Peters, Dan Aykroyd, Martin Short,Hugh Dancy, Oliver Platt — it’s a musical, a comedy, “Legends of Oz” opens Friday.