In a suit other than a suit filed by a governmental entity requesting termination of the parent-child relationship or appointment of the entity as conservator of the child, the court may not appoint:
(1) an attorney to serve in the dual role; or
(2) a volunteer advocate to serve as guardian ad litem for a child unless the training of the volunteer advocate is designed for participation in suits other than suits filed by a governmental entity requesting termination of the parent-child relationship or appointment of the entity as conservator of the child.