cad/freecad: fix build with opencascade 7.6.0
subcomponent smesh needs some minor massaging, already done upstream
PR: 259354
Reported by: thierry@
Obtained from: https://github.com/FreeCAD/FreeCAD/commit/6f3b00d67ec0bd0072b7b493e2a38d2a2e3af27d