MHR API - Add Rejection Letter (Staff Audit History and QS Registrations Table)

[cameron-eyds]

• In the UI MHR staff review table when a registration is rejected include a link to download the rejection letter report.
• In the UI MHR registrations table if the MH has a change registration that has been reviewed and rejected by staff, include a child item for the MH in the API response that includes information about the rejection and a link to download the rejection letter report.