docs: display last canary publish date in human-readable format

[Josh-Cena]

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

Made a mistake in #7334: the last publish date could be a little more readable.

Test Plan

Test links

Deploy preview: https://deploy-preview-7367--docusaurus-2.netlify.app/community/canary/

Related issues/PRs

[netlify]

✅ [V2]

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[github-actions]

⚡️ Lighthouse report for the deploy preview of this PR

URL	Performance	Accessibility	Best Practices	SEO	PWA	Report
/	🟠 67	🟢 100	🟢 100	🟢 100	🟢 90	Report
/docs/installation	🟠 82	🟢 99	🟢 100	🟢 100	🟢 90	Report

[github-actions]

Size Change: 0 B

Total Size: 811 kB

ℹ️ View Unchanged

Filename	Size
website/.docusaurus/globalData.json	52.3 kB
website/build/assets/css/styles.********.css	105 kB
website/build/assets/js/main.********.js	615 kB
website/build/index.html	38.8 kB

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