Members from shared projects or shared groups are not listed

Summary

When using the group members API resource, we cannot get invited groups that are then also members as per the recent share groups with other groups feature released in 13.1 (GitLab.com SaaS environment).

Members from shared projects are also not listed on:

• group members page

Members from shared groups are not listed on:

• group members page
• project members page

Steps to reproduce

• Create a group with group_invited as a title and add direct members on it
• Create another group with group_with_project as a title
• From the group_with_project invite the group group_invited with a developer role
• Request the API using the following request

# :id is the id of the group group_with_projects
GET /groups/:id/members

What is the current behavior?

Only direct members or inherited ones (if /all is used in the query) from the group_with_projects will be retrieved in the response. we don't get the members from the invited group.

What is the expected correct behavior?

It would be great to get the members from the invited group(s) also (unless we can retrieve the shared groups in another way??). This change should be reflected in the UI.