WASHINGTON — Steve Bannon, a longtime ally of former President Donald Trump, was sentenced Friday to serve four months behind bars after defying a subpoena from the House committee investigating the Jan. 6 insurrection at the U.S. Capitol.The judge allowed Bannon to stay free pending appeal and also imposed a fine of $6,500 as part of the sentence. Bannon was convicted in July of two counts of contempt of Congress: one for refusing to sit for a deposition and the other for refusing to provide documents.U.S. District …