Database Picker fields use ID instead of display value in Customer email notifications

Steps to Reproduce

1. Create a Database Picker field
   • You can follow this example
2. Add the field into a Jira Service Management Project's request
3. Edit the Jira Service Management Project's Customer Notifications (Issue Created) to include the request details: ${request.details}
4. Raise a request inputting value into the Database Picker from the Customer Portal

Expected Behaviour

The sent Customer Notification would show the selected Database Picker fields display value

This is how it looks like in the Request (Customer Portal side)

Actual Behaviour

The sent Customer Notification would show the selected Database Picker fields ID value instead