WebVR: Removed unnecessary WebXR check.

examples/js/vr/WebVR.js

@@ -169,7 +169,7 @@ THREE.WEBVR = {
 
 		}
 
-		if ( 'xr' in navigator && 'isSessionSupported' in navigator.xr ) {
+		if ( 'xr' in navigator ) {
 
 			var button = document.createElement( 'button' );
 			button.style.display = 'none';