update image tracking example

Author: marwie

documentation/how-to-guides/scripting/image-tracking.md

@@ -70,25 +70,17 @@ export class OnImageFound extends Behaviour {
 The `WebXRImageTracking` component dispatches an `image-tracking` event every frame when images are being tracked. The event's `detail` contains an array of `WebXRTrackedImage` objects.
 
 ```ts
-import { Behaviour, WebXRImageTracking, WebXRTrackedImage } from "@needle-tools/engine";
+import { Behaviour, WebXRImageTracking } from "@needle-tools/engine";
 
 export class ImageTrackingHandler extends Behaviour {
     onEnable() {
-        // Get the WebXRImageTracking component in the scene
         const tracker = this.gameObject.getComponent(WebXRImageTracking);
-        tracker?.addEventListener("image-tracking", this.onImageTracking);
-    }
-
-    onDisable() {
-        const tracker = this.gameObject.getComponent(WebXRImageTracking);
-        tracker?.removeEventListener("image-tracking", this.onImageTracking);
-    }
-
-    private onImageTracking = (event: CustomEvent) => {
-        const trackedImages: WebXRTrackedImage[] = event.detail;
-        for (const img of trackedImages) {
-            console.log(img.url, img.state);
-        }
+        // The event is fully typed — event.detail is WebXRTrackedImage[]
+        tracker?.addEventListener("image-tracking", event => {
+            for (const img of event.detail) {
+                console.log(img.url, img.state);
+            }
+        });
     }
 }
 ```