[examiner] Filter out sites user does not have access to

[CamilleBeau]

Brief summary of changes

This PR restricts the examiner sites shown in the examiner module to only the sites that the user has access to in the case that the user does not have the "All sites" permission for the examiner module.

• Have you updated related documentation?

Testing instructions (if applicable)

1. Create a user with the "Examiner: Add and Certify Examiners - Own Sites" permission. Give this user access to some but not all sites
2. Access the examiner module with that user
3. Make sure that the module loads and that the "Site" column in the filterable datatable only includes the sites that the user has access to
4. Give the user the "Examiner: Add and Certify Examiners - All Sites" permission
5. Make sure that the "Site" column now shows all sites, not only the sites that the user has permission to.

Link(s) to related issue(s)

• Resolves [examiner] Blank rendered for site user not part of #9704

[driusan]

@GeorgeMurad do you have time to test/review?