[BD-46] refactor: removed unused SCSS variables

[PKulkoRaccoonGang]

Description

• removed unused SCSS variables.

Merge Checklist

• If your update includes visual changes, have they been reviewed by a designer? Send them a link to the Netlify deploy preview, if applicable.
• Does your change adhere to the documented style conventions?
• Do any prop types have missing descriptions in the Props API tables in the documentation site (check deploy preview)?
• Were your changes tested using all available themes (see theme switcher in the header of the deploy preview, under the "Settings" icon)?
• Were your changes tested in the example app?
• Is there adequate test coverage for your changes?
• Consider whether this change needs to reviewed/QA'ed for accessibility (a11y). If so, please add wittjeff and adamstankiewicz as reviewers on this PR.

Post-merge Checklist

• Verify your changes were released to NPM at the expected version.
• If you'd like, share your contribution in #show-and-tell.
• 🎉 🙌 Celebrate! Thanks for your contribution.

[netlify]

✅ Deploy Preview for paragon-openedx ready!

Built without sensitive environment variables

Name	Link
🔨 Latest commit	7442879
🔍 Latest deploy log	https://app.netlify.com/sites/paragon-openedx/deploys/65551f810e28c2000827fbff
😎 Deploy Preview	https://deploy-preview-2817--paragon-openedx.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[openedx-webhooks]

Thanks for the pull request, @PKulkoRaccoonGang!

When this pull request is ready, tag your edX technical lead.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (84f7b9b) 92.89% compared to head (7442879) 92.83%.
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2817      +/-   ##
==========================================
- Coverage   92.89%   92.83%   -0.07%     
==========================================
  Files         235      235              
  Lines        4333     4240      -93     
  Branches     1053     1029      -24     
==========================================
- Hits         4025     3936      -89     
+ Misses        304      300       -4     
  Partials        4        4              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[monteri]

Only concern here that the variables can be used on the user's side. But anyway I prefer to remove them and assume that users don't use them

[viktorrusakov]

I checked with github search and I don't see any of these variables used in any of openedx org's repos, also brand-edx.org does not use them, so it should be safe to delete them.

[openedx-webhooks]

@PKulkoRaccoonGang 🎉 Your pull request was merged! Please take a moment to answer a two question survey so we can improve your experience in the future.

[openedx-semantic-release-bot]

🎉 This PR is included in version 21.7.2 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[openedx-semantic-release-bot]

🎉 This PR is included in version 22.0.0-alpha.18 🎉

The release is available on:

• npm package (@alpha dist-tag)
• GitHub release

Your semantic-release bot 📦🚀