Add figma registry to npm

[ryanntt]

✍️ Proposed changes

Figma Make has its own npm registry and require leafygreen-ui packages to be added to it. See [Figma docs].(https://developers.figma.com/docs/code/working-with-npm/)

• Added Figma npm token to Github screens
• Added figma registries to .npmrc and Github actions so that leafygreen-ui packages are visible and installable.
• Upgraded pnpm to 10.27 to fix ${VAR} interpolation in the .npmrc file. See the screenshot below:

Warning in Github action log

Github secret

✅ Checklist

For bug fixes, new features & breaking changes

• I have added stories/tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

🧪 How to test changes

• All pr.yml jobs pass: Build, Lint, Chromatic, Tests, Validate
• No auth errors in each job's Install Dependencies step logs

[changeset-bot]

⚠️ No Changeset found

Latest commit: a55bffc

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

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[github-actions]

Coverage after merging ryan/publish-figma-private-registry into main will be

79.68%

Coverage Report for Changed Files

File	Stmts	Branches	Funcs	Lines	Uncovered Lines