Compatibility for PHP 8.0

[ffauvel]

Passing the $first and $second parameters in reverse order to implode has been deprecated since PHP 7.4 and is removed since PHP 8.0; should be the first parameter and the second

🎫 Ticket

[367244]

🗒️ Description

Wordpress VIP is now enforcing the use of PHP 8.0 on november 15th. We scan the event-tickets plugin and found out there is 2 compatibility issue.

The first one is fix here with this PR

✔️ Checklist

• [x] My code is tested.