[service-worker-mock] Triggering a 'notificationclick' does not pass 'action' to the NotificationEvent

[wesleyorbin]

Hello! Thanks for creating and maintaining the server-worker-mock package. It's been super helpful for our service worker testing. However, we are having one issue when testing actions in our notificationclick event listener.

It seems that when handling the notificationclick event, the eventHandler pushes all arguments to the notification property, making it impossible to add an action to the NotificationEvent through self.trigger('notificationclick').

If you don't have a CLA to sign, I would be happy to push up a fix for this, as it should be relatively simple.

[zackargyle]

Hey! I finally got this packaged moved over to my person account, which means no CLA! Happy to review a pull request.