We first knew her in the middle 1950s as "Happy Hotpoint," the dancing spokesperson for Hotpoint Appliance commercials. We would hear her voice but see only her shapely legs a few years later when she won the role of "Sam," the mobile telephone operator on David Janssen's first TV series "Richard Diamond, Private Detective." Success and television immortality would arrive in 1961 when she was chosen for the role of "Laura Petrie" on the CBS sitcom "The Dick Van Dyke Show." When that series concl