Notwithstanding any other law of the State effective on or before June 30, 1973, or any local law, the restrictions imposed by this subtitle are the only restrictions on the political activities of an employee of a governmental entity, except for restrictions: imposed on an employee of a local board of elections by § 2–301 of the Election Law Article; or provided in or authorized by the Montgomery County Charter and imposed on: an officer or employee of the Montgomery County government who serves in a quasi–judicial capacity; or a member of a Montgomery County board or commission who serves in a quasi–judicial capacity.