As a Service Desk Customer, I'm unable to export my tickets.

As a Service Desk Customer, I'm unable to export my tickets.

Steps to reproduce:
As admin

1. Disable the option "Enable Xporter for all projects and all users"
2. Create a permission Scheme that allows Users with the role Service Desk Customer to export a template on a Service Desk Project

As an anonymous

1. Create a Service Desk Customer account
2. Create a new ticket via Customer Portal
3. Try to export it
4. Xporter will show an error message because the current user doesn't have access to the export progress