mod_choice responses export does not respect user identity fields setting or viewuseridentity capability

Steps to reproduce:

• Go to /admin/settings.php?section=userpolicies and add the idnumber profile field to $CFG->showuseridentity
• Create a student user S and fill his idnumber profile field
• Create two teacher users T and U
• Create a new teacher role C which has the moodle/site:viewuseridentity capability
• Create a new teacher role C' which has not the moodle/site:viewuseridentity capability
• Create a course
• Enrol the student user S with the student role into the course
• Enrol the teacher user T with the teacher role C into the course
• Enrol the teacher user U with the teacher role C' into the course
• Login as teacher user T
• Add a choice activity to the course and add some options
• Login as student user S
• Add your vote to the choice activity
• Login as teacher user T
• Download the choice results from the choice activity
• Login as teacher user U
• Download the choice results from the choice activity

Expected results:

• Teacher user T should see the idnumber of student user S in the choice results export
• Teacher user U should not see the idnumber of student user S in the choice results export

Actual results:

• Both teachers see the idnumber of student user S in the choice export

Conclusion:

• mod_choice does not respect a teacher's moodle/site:viewuseridentity capability when exporting the choice results