Designer: Assert url scheme of the component

Type is not parsed if the url scheme is incorrect

Change-Id: Ia5cdf2887c73769a3c1bb6d8965426b0ff7e688c
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

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

@@ -1765,6 +1765,7 @@ QUrl Model::fileUrl() const
   */
 void Model::setFileUrl(const QUrl &url)
 {
+    Q_ASSERT(url.isValid() && url.isLocalFile());
     Internal::WriteLocker locker(d.get());
     d->setFileUrl(url);
 }