(a) No contract of employment, insurance, relief benefit, or indemnity for injury or death entered into by or on behalf of any employee nor the acceptance of any insurance, relief benefit, or indemnity by the person entitled thereto shall constitute any bar or defense to any action brought to recover damages for personal injuries to, or death of, the employees.
(b) However, upon the trial of the action, the defendant may set off therein any sum it has contributed toward any insurance, relief benefit, or indemnity that may have been paid to the injured employee, or, in case of death, to his or her personal or legal representative.