Fixed notification logic to ensure check in and out emails are delivered

[marcusmoore]

Description

In this PR, email notifications are now sent before webhook notifications to ensure their deliverability in the cases where the webhook notification fails.

In addition, webhook that do fail are logged at the debug level as opposed to the error level that was used before.

Type of change

• Bug fix (non-breaking change which fixes an issue)

[shortcut-integration]

This pull request has been linked to Shortcut Story #23453: invalid slack channel stops checkin/checkout emails from sending.

[what-the-diff]

PR Summary

• Improvement to Exception Handling
  The code now includes a new tool named 'GuzzleHttp\Exception\ClientException' in the CheckoutableListener.php file. This tool allows for better handling of specific errors that may occur during the system's operation.

• Adjustment to Webhook Notification Check
  The verification for whether a webhook notification should be sent has been moved to occur after the notification has already been issued. This change has been implemented in both generic notifications and more specific onCheckedIn() notifications.

• Logging of ClientException
  When issuing notifications (both checkout and checkin), if the ClientException tool detects an error, the system will now record a detailed log of this event. These logs will make it easier to recognize and address issues going forward. The same function has also been implemented for the onCheckedIn() system notifications.

[snipe]

This looks great, thanks @marcusmoore!