SEASON FINALE: Part 1 of 2. Tonight the finales of Idol and The Voice go head to head, which ought to be interesting, at least in terms of after-the-fact network boasting. But for now, in this first half of a two-part finale, The Voice presents its four finalists, who sing one last time to fight their way to tomorrow night’s winner’s circle. First-time judge Kelly Clarkson has one representative, Brynn Cartelli, still standing, while the show’s most victorious judge, Blak