[issue_tracker] Fix typo & cleanup close permission

[CamilleBeau]

Brief summary of changes

• Have you updated related documentation?

Testing instructions (if applicable)

1. Grant a user the "own issue" Issue tracker permission
2. Ensure that the user can only view and close their own issues
3. Add the permission to view all issues to the user
4. They should now be able to view all issues, but still only able to close their own
5. Add the permission to close own sites' issues to the user
6. They should now be able to view all issues, but only close issues from their sites
7. Add the permission to close all issues
8. The user should now be able to close all issues, including issues at sites that they do not have.

Link(s) to related issue(s)

• Resolves #NO ISSUE