A Secret Service agent guarding former first lady Jill Biden shot and injured himself in the leg at Philadelphia International Airport on Friday, according to a report. Sources told KYW that the incident took place as the Secret Service agent was escorting former President Joe Biden’s wife at the busy travel hub. Philadelphia police and other agencies were on scene Friday morning, according to a radio report from the local CBS affiliate. A medic was also on the scene before leaving, the report said. The agent’s condition was not immediately clear. A Secret Service spokesperson told The Post: “We are...