LAS VEGAS — Brett Howden scored a short-handed goal at 5:28 of the second overtime Wednesday night to give Vegas a 5-4 victory over the Utah Mammoth and put the Golden Knights one victory away from winning the first-round series.The Golden Knights take a 3-2 lead into their best-of-seven NHL playoffs series on Friday night in Salt Lake City.Vegas’ Pavel Dorofeyev’s six-on-five goal with 52.7 seconds left in regulation forced overtime and gave him the sixth playoff hat trick in franchise history. Dorofeyev had two goals in 13 career playoff games before this one.Also for the Golden Knights, Shea Theodore has a goal and assist and Jack Eichel had two assists. Carter Hart stopped 33 shots.John Marino, Lawson Crouse and Dylan Guenther scored for the Mammoth and Clayton Keller had two assists. Karel Vejmelka made 31 saves.Utah rallied in the third period when Guenther tied it at 5:54 on a rush play and Michael Carcone on a two-on-one with 7:18 left.Both teams have continued to struggled on the power play, combining to go 1 for 10. Vegas ended a scoring drought of 13 power plays when Dorofeyev scored from the right circle to make it 1-1 with 40.2 seconds left in the first period. But the Golden Knights are just 3 for 18 for the series, which is better than Utah’s 1-for-14 showing.Vegas also has two short-handed goals this series, including Howden’s from the slot to win Game 5. The Golden Knights forced the action that resulted in a faceoff in Utah’s zone. Vegas won the faceoff, leading …