Oh no, the heart sinks, another jukebox musical on Broadway. So many-Cher, Donna Summer-have been varying degrees of cringe. But after leaving Ain't Too Proud: The Life and Times of The Temptations, which opened tonight at the Imperial Theatre (to November 24), a happy revelation: This jukebox musical not only has life, it also has wit, intelligence, while also looking stunning and full of energy.