Fix permission checks in member row (backport from gitlab-org/gitlab-ee!460)
## What does this MR do?
It improves the check we use to display or not the members' access and controls in the members list.
## Are there points in the code the reviewer needs to double check?
No, I replaced an helper with just a permission check so I think it's a better solution.
## Why was this MR needed?
There were a spec failure in gitlab-org/gitlab-ee!460 because of the refactor done in the "request access" MR.
## What are the relevant issue numbers?
None.
## Does this MR meet the acceptance criteria?
- No CHANGELOG needed
- [x] Tests
- [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)
See merge request !4670
