Fix lag when going back from search results

[js0mmer]

Summary

• This has been annoying me for the past few months so I ran a bisect last night and located the culprit PR (Thinner section table scroll bar #738)
• Moved the GlobalStyles from the SectionTable to the CourseRenderPane so there should only be one of them in existence now and not a hundred
  • kind of wild that was the issue

before:

lag.before.mp4

after:

after.mp4

Test Plan

Try on both staging and prod:

1. Load a bunch of search results e.g. i've been searching COMPSCI and scrolling down until I reach the research classes
2. Click back
3. Compare how long it takes

Issues

Closes #790

[KevinWu098]

Wait if that's the fix this is so goated

[KevinWu098]

So goated. Based use of git bisect. Banger PR. LGTM tested locally.

[MinhxNguyen7]

Amazing