Downloads a specific backup for an application as a ZIP archive.
appId-orgId.application/zipattachment; filename="backup-{appId}-{backup_id}.zip"error if not successful.UNAUTHORIZED: The user is not authenticated or lacks sufficient permissions.FORBIDDEN: The user does not have permission to access the application.APP_NOT_FOUND: The specified application does not exist.BACKUP_NOT_FOUND: The specified backup does not exist.BACKUP_DATA_NOT_FOUND: The backup data could not be retrieved.