FEM: mesh api, fix get nodes by face, credits go to user _UR
FEM: mesh api, fix get nodes by face, credits go to user _UR

Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master,Fat-Zer/FreeCAD_sf_master