Fix WebXR Haptics example when entering VR from Oculus Browser button (#30859)

* Fix WebXR Haptics example when entering VR from Oculus Browser button

* Remove redundant event listener for XRButton click in haptics example

examples/webxr_xr_haptics.html

@@ -140,14 +140,13 @@
 				renderer.setPixelRatio( window.devicePixelRatio );
 				renderer.setSize( window.innerWidth, window.innerHeight );
 				renderer.setAnimationLoop( animate );
+				renderer.xr.addEventListener( 'sessionstart', () => initAudio() );
 				renderer.shadowMap.enabled = true;
 				renderer.xr.enabled = true;
 				container.appendChild( renderer.domElement );
 
 				document.body.appendChild( XRButton.createButton( renderer ) );
 
-				document.getElementById( 'XRButton' ).addEventListener( 'click', initAudio );
-
 				// controllers
 
 				controller1 = renderer.xr.getController( 0 );