Blake Lively is sorry for being a “Gossip Girl.”The 36-year-old actress issued a statement Friday on her Instagram Story expressing regret over poking fun at Kate Middleton’s Photoshop fail prior to the Princess of Wales, 42, revealed her cancer diagnosis. “I’m sure no one cares today but I feel like I have to acknowledge this,” Lively wrote hours after Kensington Palace released Middleton’s video announcement.