By Marisa Schultz EXCLUSIVE: Rep. Elise Stefanik, the House GOP conference chairwoman, is throwing her support behind a first-time Republican candidate who’s running to defeat longtime Democratic Sen. Patty Murray in Washington.  Stefanik is backing Tiffany Smiley and will put the resources of her political action committee, Elevate PAC, into flipping the traditionally blue state during the 2022 midterm elections.  “I…