By Jan Wolfe WASHINGTON (Reuters) -A New Mexico county commissioner who founded a group called “Cowboys for Trump” is facing trial on Monday on charges related to the Jan. 6, 2021, attack on the U.S. Capitol, in an important test for prosecutors that could affect other criminal cases. A federal judge in the District of Columbia began the trial for Couy Griffin, who is charged with breaching a restricted area protected by the U.S. Secret Service and engaging in disorderly conduct in that area. The trial is expected to end later on Monday. U.S. criminal defendants have a right to a jury trial, b…