build: replace yarn with pnpm

[AriPerkkio]

Issue:

• Part of [Meta]: Monorepo future improvements #348
• Stacks on build: embedded packages from npm #400

What Changed

Replaces yarn with pnpm.

How to test

• CI Pass
• Test each preview project in separate projects:
  • Cypress
  • Playwright
  • Vitest

[changeset-bot]

⚠️ No Changeset found

Latest commit: 71a4fbf

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.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

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[pkg-pr-new]

Open in StackBlitz

pnpm add https://pkg.pr.new/@chromatic-com/cypress@71a4fbf -D

pnpm add https://pkg.pr.new/@chromatic-com/playwright@71a4fbf -D

pnpm add https://pkg.pr.new/@chromatic-com/vitest@71a4fbf -D

commit: 71a4fbf

[JReinhold]

🍾