Remember last year when the plastic devices placed in Times newsboxes to promote Mission: Impossible III kept prompting frightened calls to bomb squads? Well, the U.S. Attorney's office here has negotiated a $75,000 settlement to be paid by the Times, Paramount Pictures and Allied Advertising. The deal only covers the phony "bomb" that caused evacuation of part of the Department of Veterans Affairs medical complex in Brentwood last April. The red plastic devices with protruding wires were intended to play the M:I3 theme when the news box was opened.