change: [M3-8425, M3-8231] - Update TypeScript and Vitest

[bnussman-akamai]

Description 📝

• Updates TypeScript and Vitest 📦
• Remove npm-run-all and postinstall because we don't use them 🗑️
• I wanted to update just Typescript initially, but I was having issues getting Vitest's types to play nicely so I'm just going to give this a shot and see what happens

How to test 🧪

• Test local development
• Test production build (checking an internal preview link is sufficient)
• Verify Storybook still works locally
• Verify type-checking passes in GitHub Actions
• Verify Storybook builds in GitHub Actions for all packages
• Verify unit tests pass in GitHub Actions for all packages

As an Author I have considered 🤔

• 👀 Doing a self review
• ❔ Our contribution guidelines
• 🤏 Splitting feature into small PRs
• ➕ Adding a changeset
• 🧪 Providing/Improving test coverage
• 🔐 Removing all sensitive information from the code and PR description
• 🚩 Using a feature flag to protect the release
• 👣 Providing comprehensive reproduction steps
• 📑 Providing or updating our documentation
• 🕛 Scheduling a pair reviewing session
• 📱 Providing mobile support
• ♿ Providing accessibility support

[github-actions]

Coverage Report: ✅
Base Coverage: 82.73%
Current Coverage: 85.96%

[dwiley-akamai]

Test local development ✅
Internal preview link ✅
Storybook still works locally ✅
Type-checking passes in GitHub Actions ✅
Storybook builds in GitHub Actions for all packages ✅
Unit tests pass in GitHub Actions for all packages ✅

Let's add a Tech Story changeset for this 👍🏾

[cpathipa]

@bnussman Thank you for updating TS and Vitest, confirming on the verification steps.