If any part of this chapter is adjudged unconstitutional by the courts and the adjudication has the effect of invalidating any payment of compensation under this chapter, the period intervening between the time the injury was sustained and the time of the adjudication shall not be computed as part of the time prescribed by law for the commencement of any action against the employer in respect of the injury, but the amount of any compensation paid under this chapter on account of the injury shall be deducted from the amount of damages awarded in the action in respect to the injury.