Fix quiz display for non-admins

[rtibbles]

Summary

• Displaying exams in learn was using the ClassroomResource which with the security fixes in API and CSV fixes #9523 is no longer accessible to non-admins
• Updates the code to use the LearnerClassroomResource that is used in the rest of learn

References

Fixes #9544

Reviewer guidance

Can you view a quiz as a learner? (must not be an admin or superadmin)

Screencast.from.06-30-2022.12.34.31.PM.webm.mp4

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Testing checklist

• Contributor has fully tested the PR manually
• If there are any front-end changes, before/after screenshots are included
• Critical user journeys are covered by Gherkin stories
• Critical and brittle code paths are covered by unit tests

PR process

• PR has the correct target branch and milestone
• PR has 'needs review' or 'work-in-progress' label
• If PR is ready for review, a reviewer has been added. (Don't use 'Assignees')
• If this is an important user-facing change, PR or related issue has a 'changelog' label
• If this includes an internal dependency change, a link to the diff is provided

Reviewer checklist

• Automated test coverage is satisfactory
• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md

[marcellamaki]

This looks good to me

Code makes sense, and I've checked:
Taking quiz as learner

Learner quiz report

Coach: Difficult Questions

Coach: Learner report

Coach: Quiz preview

Not sure if I have missed anything in the critical workflows, @radinamatic - but if otherwise, this should be good to merge.

[radinamatic]

Tested with the DEB asset in Ubuntu 18.04, and with APK on Android 9.0 phone, all quiz learner and coach workflows look good!

[radinamatic]

LGTM 💯 !

[radinamatic]

@rtibbles Just a reminder that this should be ported to develop as the same issue is extant there (confirmed by @pcenov who did a critical workflows pass on this build today).