fix(feedback): add a missing call of Actor.appendToDom method when DOMContentLoaded event is triggered (#12973)

Fixing a missing paranthesis to call `appendToDom` on `DOMContentLoaded`
event.

Fixes #12970

Author: jaspreet57

packages/feedback/src/core/integration.ts

@@ -282,7 +282,7 @@ export const buildFeedbackIntegration = ({
         }
 
         if (DOCUMENT.readyState === 'loading') {
-          DOCUMENT.addEventListener('DOMContentLoaded', () => _createActor().appendToDom);
+          DOCUMENT.addEventListener('DOMContentLoaded', () => _createActor().appendToDom());
         } else {
           _createActor().appendToDom();
         }