Admins are seeing their own group and cert link requests instead of the users requests

[jacogasp]

When an administrator is navigating a user page, for example /dashboard#!/user/1d528512-477f-4f9c-b7de-8b7bd27dceeb, the Group Requests and X.509 certificate linking requests panels should show the user's requests.
Instead, the admin requests are shown independently from the user page that they are inspecting.

This is due to the wrong username queried to the API: if we are navigating the user page of the user with userName = foo, the query should be /iam/group_requests?status=PENDING&username=foo.
Instead, the query /iam/group_requests?status=PENDING&username=admin (supposing that admin is the administrator's username) is always performed, no matter which user page the admin is watching.