By Jan Wolfe and Sarah N. Lynch WASHINGTON (Reuters) – A former New York City police officer was found guilty on Monday of assaulting a Washington, D.C., police officer during the Jan. 6, 2021, riot at the U.S. Capitol by supporters of then-President Donald Trump, handing prosecutors another win at trial, a Justice Department spokesman confirmed. A federal jury in the District of Columbia rejected arguments by Thomas Webster, 56, that he was acting in self-defense when he struck a Washington officer with a flagpole and tackled him. A spokesman for the U.S. Attorney’s Office said Webster will b…