pymel_test: exclude gui tests if not in gui mode
pymel_test: exclude gui tests if not in gui mode

leonsooi/pymel,juggernate/pymel,AtonLerin/pymel,david-lassonde-adsk/pymel,shrtcww/pymel,assumptionsoup/pymel,leonsooi/pymel,assumptionsoup/pymel,david-lassonde-adsk/pymel,shrtcww/pymel,AtonLerin/pymel,juggernate/pymel