Employee webhooks: `employee.deleted` event now includes email

Previously, the employee.deleted webhook event included only the employee ID, assuming the ID could be used to retrieve additional employee details if needed.

However, since the employee record is no longer available once deleted, it wasn't possible to retrieve any other data via the API. To solve this, we've added the employee's work email address to the employee.deleted event payload.

This allows you to retain a reference to the deleted employee even if the rest of their data is no longer accessible.

To learn more, see employee webhook events.