Onetime cable television star Ashleigh Banfield - a publicity magnet even before she achieved celebrity in the aftermath of 9/11 - is out at NBC News. The 36-year-old former rock singer - once a fashion icon for her blond tresses and her ever-present on-air glasses, but whose career took a slide after she dyed her hair dark brown - joined the network's MSNBC outlet four years ago, and has been working without a contract since late January. "Regrettably, we were unable to agree on a new assignment for her," an NBC News spokeswoman told me yesterday. "We thank her for...