Refactor sidebar test

[lamATnginx]

Proposed changes

• Added test for product selector
• Removed overlap from needing to test every single link and dropdown.
• Removed unneeded product-selector.js

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING document
• If applicable, I have added tests that prove my fix is effective or that my feature works
• If applicable, I have checked that any relevant tests pass after adding my changes
• I have updated any relevant documentation (README.md and CHANGELOG.md)

[github-actions]

✅ Deploy Preview will be available once build job completes!

Name	Link
😎 Deploy Preview	https://frontdoor-test-docs.nginx.com/previews/nginx-hugo-theme/451/

---

[lamATnginx]

As seen in the workflow, we have made a huge improvement from 2-3 minutes on the running test step to just ~1 minute.

[TasoOneAsia]

Additionally approved :)

Tests are speeding along locally and I'm not getting those random failures I was getting pre-refactor 🥳

One clarifying question around whether a state is valid/invalid.