The GetAppsAsAdmin endpoint currently does not return information about Links defined in an app. To get the complete picture of what content an app consists of links should be part of the API response.
If you would like to suggest feature improvements, you may vote the idea and comment here to improve this feature. It is a place for customers provide feedback about Microsoft Office products . What’s more, if a feedback is high voted there by other customers, it will be promising that Microsoft Product Team will take it into consideration when designing the next version in the future.