Data export permission-related improvements

We’ve improved the data export-related permissions in the Developer Dashboard. Only a Product Owner or an Admin can export data from the ‘Users’ page.

The rest of the roles can either have view-only permissions (for example Developer or Support) or be completely blocked from viewing Users (for example Accountant).

The ‘Download’ button will now be hidden for roles with view-only permission. The API will also block a request to the .csv endpoint.