Not Possible to Retrieve Space Icon Download URI from V2 endpoints

Issue Summary

This is reproducible on Data Center: (yes) / (no)

Steps to Reproduce

In V1, it is possible to use this endpoint: Get URI to download attachment to retrieve a URI to download an attachment. This endpoint requires the context: attachment ID & content ID of attachment's container.

In the context of space icon, it is possible to fetch this context by:

• Hitting `wiki/rest/api/space?expand=icon`
  • Get response in format: /download/attachments/<entity-id>/...
• Pull entity ID out of response structure and hit: `wiki/rest/api/content/<entity-id>/child/attachment` to retrieve attachment ID
• Finally you can hit `/wiki/rest/api/content/<entity-id>/child/attachment/<attachment-id>/download` to retrieve the icon download URI

In V2, it is not possible to fetch this attachment ID context. We would need to rely on a deprecated V1 endpoint: Get attachments. A workaround needs to be put in place so apps can access the download URI of space icons without the need for a deprecated endpoint.

Expected Results

Apps can access download URI for Space Icons without the need for a deprecated endpoint.

Actual Results

Apps can only access the download URI for Space Icons by using deprecated endpoints.

Workaround

The only work around is to continue using deprecated endpoints. This work around will not work once these endpoints are removed from public access, so this needs to be addressed ASAP.