Executive security has been front and center in recent days in the wake of a man fatally shooting UnitedHealthcare CEO Brian Thompson. Some of the U.S. companies with the largest market capitalizations allocate sizable sums for personal security and other measures to help keep their CEOs safe. CVS PULLS DOWN EXECUTIVE PHOTOS FROM WEBSITE AMID MANHUNT FOR UNITEDHEALTHCARE CEO KILLERThe iPhone maker said in its proxy statement that it "provide[s] …