fix(a11y): move focus algolia-search focus back to search input on Escape

[mxschmitt]

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

When using Tab to navigate through the website and enter the Algolia search, type something but decide to go back (Esc) the focus gets lost. It should go back where it came from (search input).

Test Plan

1. Tab through the page until you reach the Search input
2. Press Enter to open the Popup
3. Enter something and press Esc

Expected: Focus is back in the search input
Actual: Focus is lost

Test links

Deploy preview: https://deploy-preview-9945--docusaurus-2.netlify.app/

Related issues/PRs

Fixes #9917

[netlify]

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[github-actions]

⚡️ Lighthouse report for the deploy preview of this PR

URL	Performance	Accessibility	Best Practices	SEO	PWA	Report
/	🟠 58	🟢 98	🟢 96	🟢 100	🟠 88	Report
/docs/installation	🟠 66	🟢 96	🟢 100	🟢 100	🟠 88	Report
/docs/category/getting-started	🟠 75	🟢 100	🟢 100	🟢 90	🟠 88	Report
/blog	🟠 70	🟢 100	🟢 100	🟢 90	🟠 88	Report
/blog/preparing-your-site-for-docusaurus-v3	🟠 62	🟢 96	🟢 100	🟢 100	🟠 88	Report
/blog/tags/release	🟠 71	🟢 100	🟢 100	🟠 80	🟠 88	Report
/blog/tags	🟠 75	🟢 100	🟢 100	🟢 90	🟠 88	Report

[slorber]

Thanks 👍 makes sense