JAZZ AT THE PHILHARMONIC j is always a lucky booking lor Ella; Fitzgerald. When she got off the road after last year’s tour, she went right into the shooting for “'Pete Kelly’s Blues,” her first big picture break. Now. on the eve of this season's JATP series, she’s received word that they want her back at Moca mho as soon as possible. And that’s the place where she really yearned to click, because the “ a gent” who got her the I job there was Marilyn Monroe.