Where are you sequel? In 2000, at just seven years old, Taylor Momsen starred as Cindy Lou Who opposite Jim Carrey’s green grinch in the classic holiday film “How the Grinch Stole Christmas.” But fans might not see the cast reunite for a sequel any time soon, with the actress, 32, exclusively telling The Post that nothing is in the works. “Not that I know of,” she said while attending Steven Tyler’s 7th annual Jam of Janie Grammys watch party on Sunday. “Some things don’t touch,” Momsen added. “