Do not display the 'mahara' institution for a site admin on the profile page

[Kristina Hoeppner]

Reported at https://mahara.org/interaction/forum/topic.php?id=9253&post=36488

We display the main role of a person on their profile page, i.e. 'Member', 'Staff', 'Support administrator', 'Institution administrator', and 'Site administrator'. For roles in an institution, the name of the institution is linked so people can find out who the staff, institution admins, and institution support admins are to get in touch with them.

For the site administrator, the 'institution' 'mahara' is linked. That is the 'site institution'. Since that is not a proper institution but the site, it doesn't have a contacts page. It would be better not to display the institution name as it's a role that is across the entire site.