QmlDesigner: Add back empty entry to ordered properties

The empty entry defines where default properties and signals
end up.

Change-Id: I9a17dbbe80374e45e78318608c67a213441aef4f
Reviewed-by: Brook Cronin <brook.cronin@qt.io>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/plugins/qmldesigner/designercore/model/modeltotextmerger.cpp

@@ -386,6 +386,8 @@ PropertyNameList ModelToTextMerger::propertyOrder()
                                                 PropertyName("lineHeight"),
                                                 PropertyName("lineHeightMode"),
                                                 PropertyName("wrapMode"),
+                                                PropertyName(),
+                                                PropertyName("states"),
                                                 PropertyName("to"),
                                                 PropertyName("from"),
                                                 PropertyName("transitions")};