Out of the box, that isn't supposed to be in the CMSDesk because its a global or a Site Manager page. You can tell by looking at the page in code, the template inherits the SiteManagerPage
object.
If you wanted to include that in the CMSDesk, you'd need to clone a copy for yourself or modify the base (not recommended) and add a reference to the CMSDeskPage
so you could set permissions there. I've done this before and it works, just not ideal and easy to setup like it is now in v8.x