[Bug] 500 error clicking on website outside user's organization

Steps to reproduce:

1. Login as a non-admin user.
2. View the list of websites at https://touchpoints.app.cloud.gov/admin/websites.
3. Click on a website belonging to an organization that is not the user's organization.

 
**Expected behavior:** The user is taken to the page for the website. Or, if the user is not supposed to have access to websites outside their organization, the website should not have been returned in the list of websites.
**Actual behavior:** User is taken to an error screen.