Fix 404 on project page for unauthenticated user

Eliminate a 404 error when user is not logged in and attempts to visit
a project page.

The 404 page will still show up when user is logged in and the project
doesn’t exist or the user doesn’t have access.
Merge pull request #5752 from jhollingsworth/fix/no-404-for-project

Fix 404 on project page for unauthenticated user