Highlight selected course & Hide waitlist when there isn't one

[szeckirjr]

Description

This PR highlights the current course looking at the user's URL and it also fixes a bug that shows full waitlists for 0/0, so this hides the waitlist for those that have no total capacity for both the course sections and the scheduler sidebar.

Closes #484

Screenshots

Before

After

Checklist

• [x] The code follows all style guidelines.
• [x] The code passes all required tests.
• [ ] The code is documented.
• [ ] The code includes tests.
• [x] I have self-reviewed my changes and have done QA.

General Comments

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Name	Status	Preview	Updated (UTC)
courseup	✅ Ready (Inspect)	Visit Preview	Jul 27, 2023 0:23am