Election officials in dozens of states representing both political parties said that there was no evidence that fraud or other irregularities played a role in the outcome of the presidential race, amounting to a forceful rebuke of President Trump’s portrait of a fraudulent election. Over the last several days, the president, members of his administration, congressional Republicans and right wing allies have put forth the false claim that the election was stolen from Mr. Trump and have refused to accept results that showed Joseph R. Biden Jr. as the winner.