Tinsley Mortimer no longer has her reality show, “High Society,” but she does have a book deal. Sources say the socialite/handbag designer inked a deal with Simon & Schuster for a novel. The Tinz has written long form before, having contributed a chapter on “interpersonal skills” to 2008’s “The Park Avenue Diet,” by Dr. Stuart Fisher. Page Six reported last month that the CW canceled “High Society” after one season, during which Mortimer was disappointed by her lack of editorial control.