Use OCCT Handle macro for Handle_ classes

This is the result of running OCCT's upgrade script provided
with OCCT 7.0. See
https://www.opencascade.com/content/freecad-occt710-and-windows-rtti-data-missing#comment-form
and
https://www.forum.freecadweb.org/viewtopic.php?f=4&t=21405&start=120#p169019
for why this is necessary for OCCT >= 7.1

src/Mod/Part/Gui/DlgExtrusion.cpp

@@ -319,7 +319,7 @@ void DlgExtrusion::autoSolid()
             if (sh.IsNull())
                 return;
             ShapeExtend_Explorer xp;
-            Handle_TopTools_HSequenceOfShape leaves = xp.SeqFromCompound(sh, /*recursive= */Standard_True);
+            Handle(TopTools_HSequenceOfShape) leaves = xp.SeqFromCompound(sh, /*recursive= */Standard_True);
             int cntClosedWires = 0;
             for(int i = 0; i < leaves->Length(); i++){
                 const TopoDS_Shape &leaf = leaves->Value(i+1);