[FRONTEND] Use skeleton accordions for admin semesters view

[jji05]

Is your feature request related to a problem? Please describe.

There is a brief flicker of No semesters found when the page initially loads. Would be far better to use a loading state or skeleton instead of this.

Could maybe recycle FAQ skeleton.

Additional context

BEFORE MERGING

• Storybooks created where possible
• Tested with react testing library
• Tests written for critical interactions
• PR Reviewed (For non-trivial changes)
• Changes tested after rebasing on master or merging in master (hint: git fetch origin master:master, then git rebase master or git merge master)
• All required PR checks passing