Fixes #1420

Props mkrndmane, ryelle.

This PR forces login for editing tickets that are currently unconfirmed.

Changes

• Adds user_must_confirm_ticket that checks if the ticket is unconfirmed. Reference
• Passes along all tix_ parameters found in $_REQUEST to the final destination. Reference
  • I don't understand is why the original code checked for isset( $_REQUEST['tix_tickets_selected'] ) before passing along the parameters. I would assume we could pass them along in all cases.

How to test

1. Purchase multiple tickets. (Stripe test cards, Stripe test keys)
   • Set a ticket to I don't know who will use this ticket yet
   • Set a ticket First Name/Last Name/Email.
2. While viewing an Attendees post through the admin interface list:
   • Confirm the tix_username is set to [[ unconfirmed ]]
   • Copy the edit token link address.
3. Visit that link in an incognito session.
4. Confirm you are asked to login.
   • Note if you login with the same account you purchased your ticket with, this filter will stop you. You can comment out this one and the one below it to test if you don't have a second account to use
5. Enter new details into the fields.
6. Click the "Confirm Registration" button.
7. View the attendee through the admin interface and confirm that their tix_username is set to the user that was used to log in.
8. Copy the edit token link again.
9. Log out.
10. Paste that link in your browser.
11. Update information and click "Save Attendee information"
12. Notice that you are able to update the ticket information without logging in once the user is no longer [[ unconfirmed ]].