R1:5251f08fb432

Use `window.confirm` instead of `confirm`

Summary:
This silences the following JSHint warning:

```
>>> Lint for webroot/rsrc/js/application/uiexample/notification-example.js:

Warning (W117) JSHintW117
'confirm' is not defined.

39 notification.listen(
40 'activate',
41 function() {
>>> 42 if (!confirm('Close notification?')) {
43 JX.Stratcom.context().kill()…