Since the late 1990s, drug companies have spent tens of billions of dollars on television ads, drumming up demand for their products with cheerful jingles and scenes of dancing patients.Now, some people up for top jobs in the incoming Trump administration are attacking such ads, setting up a clash with a powerful industry that has long had the courts on its side.Robert F. Kennedy Jr., President-elect Donald J. Trump’s choice for health secretary, is a longtime critic of pharmaceutical advertising on TV, arguing that it leads broadcasters to more favorable coverage of the industry and does not improve Americans’ health....