Consider sub-requirement progress in add modal choices

[SamChou19815]

Summary

This PR addresses the problem mentions in this PR comment, where the current add modal choices completely disregards whether adding a course can help increasing the requirement fulfillment progress. This PR implements the proposal I mentioned in the follow-up PR comment, in which we will compute a new stat with the course added, and check whether it can increase the sub-requirement progress. If not, then the requirement won't show up as a choice.

To be able to call the function, we must create a CourseTaken object with real credits information. Therefore, we must generate that info when we are selecting the courses, so we must use the full course json instead of the simplified one. I switched the course selector to use the full course json, and after that the simplified course json becomes unused, so I deleted it.

Test Plan

Now the bug is fixed (when I have two math classes, adding one more math class won't cause the MQR requirement to show up):

[dti-github-bot]

[diff-counting] Significant lines: 185.

[github-actions]

Visit the preview URL for this PR (updated for commit c9ed704):

https://cornelldti-courseplan-dev--pr351-add-modal-choices-co-0bji223x.web.app

_{(expires Tue, 16 Mar 2021 00:24:25 GMT)}

_{🔥 via Firebase Hosting GitHub Action 🌎}

[tcho6319]

Thanks Sam! I left some comments below:

1. I would check out NewSelfCheckCourseModal.vue b/c I think deleting courses.json might have had a side effect for that component.

Screen.Recording.2021-03-08.at.5.28.05.PM.mov

[tcho6319]

I think <input> here was for accessibility purposes. Is it ok to remove?

[SamChou19815]

I think it's not. It was there back when we have DOM manipulation and we use the input to read out the data we need instead of using emit.
The type is hidden, so the semantics is that it will also be hidden when viewed by the accessibility software, so there should be no impact on a11y.

[SamChou19815]

@tcho6319 fixed the broken self-check add modal and added some doc for full course json

[tcho6319]

LGTM! Ty Sam 😀