ci: run only a single Windows check

[angeloashmore]

Resolves: https://prismic-team.slack.com/archives/C014VAACCQL/p1784933535521479

Description

This PR reduces the Windows test CI jobs from three (Node.js 20, 22, 24) to one (Node.js 24). As a result, we cut down on failures and wait time.

Reasoning: We only need to run Node 20, 22, 24 on some OS and one Windows sanity-check.

Checklist

• If my changes require tests, I added them.
• If my changes affect backward compatibility, it has been discussed.
• If my changes require an update to the CONTRIBUTING.md guide, I updated it.

Preview

How to QA ¹

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Note

Low Risk
CI-only matrix change with no application or runtime behavior changes; slightly less Node version coverage on Windows only.

Overview
Narrows the test-win32 job in validate.yml so Windows unit tests run only on Node.js 24, instead of a matrix across 20, 22, and 24.

Linux test still exercises all three Node versions; Windows remains a single sanity check with less CI time and fewer flaky Windows-only failures.

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