[UserCap FE]: Update Banner Pending User Button Link

The designs for #332595 (closed) depict a pending members page: #321934[rt-group-owner-approved-awaiting-signup.png]

The View pending user approvals button in the namespace user cap banner is supposed to link to this page. However, it does not exist yet.

So instead, the button links to this page for now:

This link needs to be updated once the pending members page exists.