With fashion designers as moms, it’s no wonder that celebrity kids such as Kingston Rossdale, Skyler Berman, Suri Cruise and Harper Beckham are seen in today’s top fashions. “It is too much fun. It is like dressing a live doll,” Rachel Zoe said of dressing her one-year-old son Skyler with husband Rodger Berman. “He has no opinion. Every minute I have to buy …