feat(editor): Gracefully ignore invalid payloads in postMessage handler (#8096)

It's possible for browser extensions to send `message` events to an n8n window.
This change improves the already existing check to ignore invalid messages.

Fixes https://community.n8n.io/t/errors-in-the-browser-console-on-n8n-1-version/33910

packages/editor-ui/src/views/NodeView.vue

@@ -4351,7 +4351,7 @@ export default defineComponent({
 			}
 		},
 		async onPostMessageReceived(message: MessageEvent) {
-			if (!message?.data?.includes?.('"command"')) {
+			if (!message || typeof message.data !== 'string' || !message.data?.includes?.('"command"')) {
 				return;
 			}
 			try {