[Core] Enable a frame in VarSet dialog value field

The Add Property Dialog for VarSets creates an editor based on the type.
This editor has no frame by default because it is mostly used in the
property view as part of a table.  With this change we enable the frame
for the editor (the value field)

src/Gui/Dialogs/DlgAddPropertyVarSet.cpp

@@ -261,7 +261,7 @@ void DlgAddPropertyVarSet::addEditor(PropertyEditor::PropertyItem* propertyItem,
 {
     editor.reset(propertyItem->createEditor(this, [this]() {
         this->valueChanged();
-    }));
+    }, PropertyEditor::FrameOption::WithFrame));
     editor->blockSignals(true);
     propertyItem->setEditorData(
             editor.get(),