🐛Event page should state that the event is ended and prevent ticket sales

[phtaylor]

Describe the bug
Users can still purchase tickets for an event that is ended.
This can lead to people puchasing tickets for an event that is over thinking it was an upcoming event.

Expected behavior

I think the 'Continue' button should be disabled.

Logs
Add any relevant error logs. If it's an error in the browser, please include the browser console logs as well
as what endpoints are being hit and what the response from the server is.