“American Idol” starlet Ayla Brown morphed into campaign pit bull yesterday for GOP dad Sen. Scott Brown as she tore into Democrat Attorney General Martha Coakley for plunging the U.S. Senate race into the gutter. “Martha Coakley’s new negative ad represents everything that discourages young women from getting involved in politics, and as a young woman, I’m completely offended by that,” said the 21-year-old Brown. “She even spelled Massachusetts wrong in her original ad which is very embarrassing, I must say as a young woman.” The former Idol contender and Boston College senior sought to further boost her father onto...