Exam bank: Exam hiding breaks main-solution matching

[some-molasses]

Here's two exams under "CS 130", both labelled "oops it's still mathNEWS" (you'll never guess what the associated PDF was).

After I hide one, then refresh the browser, I see

These should still appear on the same row, even after one is hidden.

[KuroganeToyama]

I'm not officially assigning myself to this issue (yet), but for the record, you might wanna tell other devs to also include the API key for the UWaterloo OpenAPI, cuz just a couple of minutes ago, I was playing around with this issue and trying to upload a file to the exam bank. Since I didn't include the API key, the backend couldn't validate the term, so it produced a message in server/data/_hidden/term-list.json, and caused subsequent attempts to build the website to fail. That required me to clear the json file for things to work normally again.