QmlDesigner: Fix copying material property default values

When copying specific set of properties, old values need to be cleared
just like in case of copying all properties to ensure also default
values get copied.

Fixes: QDS-7522
Change-Id: I314ff70b6e611bec3f662b86f964d789618c1df7
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>

src/plugins/qmldesigner/components/materialbrowser/materialbrowserview.cpp

@@ -117,6 +117,8 @@ WidgetInfo MaterialBrowserView::widgetInfo()
                         mat.setVariantProperty(prop.name(), prop.toVariantProperty().value());
                     else if (prop.isBindingProperty())
                         mat.setBindingProperty(prop.name(), prop.toBindingProperty().expression());
+                    else if (!all)
+                        mat.removeProperty(prop.name());
                 }
             });
         });