Quiz manual grading: attached files not downloadable with certain permissions

When removing permission mod/quiz:viewreports attached files in essay questions are no longer downloadable, rendering the message Sorry, the requested file could not be found.

Steps to reproduce

Prerequisites:

• Course A
• Users enrolled in this course: Student S, Teacher T and Non-editing teacher N

Steps:

1. Login as admin
2. Remove the capability mod/quiz:viewreports from the role Non-editing teacher (on standard Moodle instances: admin/roles/define.php?action=view&roleid=4)
3. Logout
4. Login as Teacher T and go to Course A
5. Turn editing on
6. Add a new quiz instance:
   1. Title: "Test attachments"
7. Edit quiz
8. Add a new essay question
   1. Question name: Essay with attachments
   2. Question text: Add an attachment.
   3. Response format: No online text
   4. Allow attachments: 1
   5. Allow attachments: 1
9. Logout
10. Login as Student S
11. Go to Course A
12. Make the quiz, add example_attachment.pdf and finish attempt
13. Submit all and finish
14. Logout
15. Login as Non-editing teacher N
16. Go to Course A
17. Open the quiz "Test attachments"
18. Go to manual grading page
19. Click on "grade"
20. Click on the attached file "example_attachment.pdf
21. See the error: "Sorry, the requested file could not be found"

Optional:
Countercheck with Teacher T and see that he is able to download the attachment.