It is almost as though Joey Gargan decided to slip away before anyone noticed. And the funny thing about it is that he succeeded. So, Ted Kennedy cousin Joseph F. “Joey” Gargan, who was Kennedy’s close companion, won’t be around to answer any questions about “Chappaquiddick,” the upcoming film about the late Sen. Ted Kennedy and the death of Mary Jo Kopechne. Joey, 87, who was at Kennedy’s side that fateful night, died at his Virginia home December 12 and hardly anybody made the connection to Kennedy and Chappaquiddick