Support displaying multiple instructors in course terms

[39bytes]

Resolves #521

https://github.com/terror/mcgill.courses/assets/47371088/7a74df6a-3f7e-42ad-89ec-351e294c63b3

Additionally:

• Added immer for easy nested state updates
• Fixed key errors in some other components

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 88.11%. Comparing base (5aad6c7) to head (66073ea).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #566 +/- ## ======================================= Coverage 88.11% 88.11% ======================================= Files 44 44 Lines 6294 6294 ======================================= Hits 5546 5546 Misses 748 748 ```

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[SamZhang02]

amazing