message: Fix persistent widgets on desktop / http
  WidgetMessaging needs the URL of the widget that gets rendered into
  the iframe because that's where the postmessages will be coming from.
  Fixes
diff: @@ -430,7 +430,7 @@ export default class AppTile extends React.Component {
  // is used for is to determine the origin we're talking to, and therefore we don't need the
  // fully templated URL.
  const widgetMessaging = new WidgetMessaging(
  - this.props.app.id, this.props.app.url, this.props.userWidget, this._appFrame.current.contentWindow);
  + this.props.app.id, this._getRenderedUrl(), this.props.userWidget, this._appFrame.current.contentWindow);
  ActiveWidgetStore.setWidgetMessaging(this.props.app.id, widgetMessaging);
  widgetMessaging.getCapabilities().then((requestedCapabilities) => {
  console.log(`Widget ${this.props.app.id} requested capabilities: ` + requestedCapabilities);
  