fix: pin npm version for release publish

[xuefei1313]

Summary

• Pin the release publishing npm self-upgrade to npm@11.5.1.
• Avoid npm 12 rejecting Rush/pnpm's forwarded --no-git-checks option as an unknown CLI config.

Root cause

rush publish uses the pnpm version pinned in rush.json, and that pnpm version forwards --no-git-checks to npm publish. The workflow's unpinned npm@latest upgrade now resolves to npm 12, which fails with EUNKNOWNCONFIG.

Validation

• Workflow assertion verifies npm is pinned to 11.5.1 and does not reference npm@latest.
• YAML parsing succeeded.
• npm exec --package=npm@11.5.1 -- npm --version returned 11.5.1.
• Local pre-push hook completed rush test --only tag:package.