chore: simplify construction of test paths

[benmccann]

Pre-flight checklist

• I have read the Contributing Guidelines on pull requests.
• If this is a code change: I have written unit tests and/or added dogfooding pages to fully verify the new behavior.
• If this is a new API or substantial change: the PR has an accompanying issue (closes #0000) and the maintainers have approved on my working plan.

Motivation

Simplifies the code

Test Plan

Relying on existing tests

Test links

Deploy preview: https://deploy-preview-_____--docusaurus-2.netlify.app/

Related issues/PRs

I noticed this while working on #11042. That PR is failing the CI for reasons that seem totally unrelated to it. I can't figure out what's going on there, so thought I'd break this off separately to see if it can pass independent of those changes

[netlify]

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[github-actions]

⚡️ Lighthouse report for the deploy preview of this PR

URL	Performance	Accessibility	Best Practices	SEO	Report
/	🔴 42	🟢 98	🟢 100	🟢 100	Report
/docs/installation	🔴 48	🟢 97	🟢 100	🟢 100	Report
/docs/category/getting-started	🟠 71	🟢 100	🟢 100	🟠 86	Report
/blog	🟠 55	🟢 96	🟢 100	🟠 86	Report
/blog/preparing-your-site-for-docusaurus-v3	🔴 45	🟢 92	🟢 100	🟢 100	Report
/blog/tags/release	🟠 61	🟢 96	🟢 100	🟠 86	Report
/blog/tags	🟠 73	🟢 100	🟢 100	🟠 86	Report

[slorber]

Thanks