The esim purchased in the Sandbox cannot be activated on a real device. It is for development and testing purposes. On the other hand, Airalo is testing the installation of eSIMs internally, so it is not necessary to do it on the partner side.
In order to test the whole flow, the typical approach is once the development and internal testing are done, the partner continues in Production and makes 1-2 test orders using their Production credentials.
These test orders will be refunded just the partner needs to open a support ticket to request the refund with the reason for testing before enabling in Production app for end users.