QmlDesigner.MetaInfo: fix lazy initialization

The lazy initialization was missing for NodeMetaInfoPrivate::propertyType()

Change-Id: Ic2251df30de2187aea44fe7a48df9e5e0d635ab8
Reviewed-by: Tim Jenssen <tim.jenssen@theqtcompany.com>

src/plugins/qmldesigner/designercore/metainfo/nodemetainfo.cpp

@@ -1185,6 +1185,8 @@ bool NodeMetaInfoPrivate::isValid() const
 
 TypeName NodeMetaInfoPrivate::propertyType(const PropertyName &propertyName) const
 {
+    ensureProperties();
+
     if (!m_properties.contains(propertyName))
         return TypeName("Property does not exist...");
     return m_propertyTypes.at(m_properties.indexOf(propertyName));