Fix QuizGroup's course_id

[dgwn]

Proposed Changes

• QuizGroup fixed to have course_id of the quiz's course_id, instead of the quiz_id

Fixes #712.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (37639e6) to head (1cbfa66).
⚠️ Report is 1 commits behind head on develop.

Additional details and impacted files

@@ Coverage Diff @@ ## develop #713 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 75 75 Lines 3803 3803 ========================================= Hits 3803 3803 

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[Thetwam]

Thanks!