By Diane Bartz WASHINGTON (Reuters) – A group representing publishers such as News Corp and National Public Radio wrote to leaders of the Senate Judiciary Committee on Thursday to back two bills targeting Big Tech including one that would open up smartphone app stores to more competition. Digital Content Next, whose members also include the New York Times and Associated Press, wrote to Judiciary Committee Chairman Dick Durbin, a Democrat, and Senator Chuck Grassley, the top Republican, to back a bill aimed at reining in app stores owned by Apple and Alphabet’s Google. The group also backed a m…