A former national guard cop charged with attacking police officers with chemical spray at the U.S. Capitol on Jan. 6, 2021, pleaded guilty Thursday to felony offenses in federal court in Washington, D.C. Gregory Yetman, 47, of Helmetta, had been indicted on six crimes related to the rioting that day, including assaulting police with a dangerous weapon. He pleaded guilty to a charge of assaulting, resisting or impeding certain officers with physical contact. Prosecutors accused Yetman of being part of a mob of rioters that surrounded Capital Police Officers on the West Terrace of the Capital bu…