fix: redoc menu content is now scrollable

[lamATnginx]

Proposed changes

• Allow Redoc menu to be scrollable.

GitHub Issue:
Closes https://github.com/nginxinc/docs-platform/issues/281

Checklist

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• I have read the contributing guidelines
• I have signed the F5 Contributor License Agreement (CLA)
• I have ensured that documentation content adheres to the style guide
• If the change involves potentially sensitive changes, I have assessed the possible impact
• If applicable, I have added tests that prove my fix is effective or that my feature works
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• I have updated any relevant documentation (README.md and CHANGELOG.md)
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[github-actions]

✅ All required contributors have signed the F5 CLA for this PR. Thank you!
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[lamATnginx]

I have hereby read the F5 CLA and agree to its terms

[github-actions]

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[mjang]

The ability to scroll, with this PR, is confirmed. Thanks!