Add more tests for subgroups feature
What does this MR do?
It adds test to existing functionality:
- create subgroup by group owner
- allow subgroup in namespace selectbox on project page if you are owner of the top level group
Are there points in the code the reviewer needs to double check?
no
Why was this MR needed?
To avoid bugs like mentioned in https://gitlab.com/gitlab-org/gitlab-ce/issues/30194