WASHINGTON—Attorney General Merrick Garland has tested positive for COVID-19 and will quarantine at home for five days, the Justice Department said Wednesday. Garland is the second Cabinet official to announce a positive test result on Wednesday. Commerce Secretary Gina Raimondo also tested positive for the virus using an at-home antigen test. The two officials are among more than a dozen attendees of the Gridiron Club dinner to test positive for the virus in the past few days. Saturday night’s white-tie society affair was attended by some of the nation’s most prominent political leaders, journalists, and media executives. Tom DeFrank, the president of the Gridiron Club, said the group knew of 14 guests who had attended and then tested positive. Many of the cases involve guests who were seated at three tables, he said. “There is no way of being certain about when they first contracted COVID,” DeFrank said. “But they …