Section 135C. A contract or agreement creating or establishing the terms of a partnership, employment, or any other form of professional relationship with a social worker licensed under this chapter that includes a restriction of the right of the social worker to practice in any geographic area for any period of time after termination of the partnership, employment or professional relationship shall be void and unenforceable with respect to that restriction. This section shall not render void or unenforceable the remainder of the contract or agreement.