Remove outdated notifications

[nstringham]

If the user opens a game and plays their turn we should remove any notifications they may have informing them that it is their turn.

[nstringham]

This will probably be helpful
https://developer.mozilla.org/en-US/docs/Web/API/ServiceWorkerRegistration/getNotifications

And this
https://developer.mozilla.org/en-US/docs/Web/API/Notification/close