(Reuters) – U.S. singer, dancer and “American Idol” star Paula Abdul filed a lawsuit accusing British television executive Nigel Lythgoe of sexually assaulting her when they worked together on two popular talent shows, according to court documents. Abdul, who rose to fame as a chart-topping singer in the late 1980s, alleged in a lawsuit filed in Los Angeles County Superior Court on Friday that Lythgoe sexually assaulted her in an elevator during the early seasons of TV singing competition series “American Idol.” Lythgoe, the producer of several hit television talent competitions, allegedly gro…