[NO-JIRA][maintenance] uninstall ts-migration

[Faye (Faye-Xiao)]

When I was solving this alert(Regular Expression Denial of Service (ReDoS) in micromatc), I found the problematic library, micromatc version came from the ts-migrate as the screenshot below shows.

Since we didn't actually use ts-migrate to do TS migration, we can just remove it.

Remember to include the following changes:

• Ensure the PR title includes the name of the component you are changing so it's clear in the release notes for consumers of the changes in the version e.g [Clover-123][BpkButton] Updating the colour
• README.md (If you have created a new component)
• Component README.md
• Tests
• Accessibility tests
  • The following checks were performed:
    • Ability to navigate using a keyboard only
    • Zoom functionality (Deque University explanation):
      • The page SHOULD be functional AND readable when only the text is magnified to 200% of its initial size
      • Pages must reflow as zoom increases up to 400% so that content continues to be presented in only one column i.e. Content MUST NOT require scrolling in two directions (both vertically and horizontally)
    • Ability to navigate using a screen reader only
• Storybook examples created/updated
• For breaking changes or deprecating components/properties, migration guides added to the description of the PR. If the guide has large changes, consider creating a new Markdown page inside the component's docs folder and link it here

[Copilot]

Pull request overview

This PR removes the unused ts-migrate package and its associated npm script from the project. Since the team did not use ts-migrate for TypeScript migration, the dependency and script are no longer needed.

• Removed the ts-migrate npm script from package.json
• Removed the ts-migrate devDependency from package.json

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[skyscanner-backpack-bot]

Visit https://backpack.github.io/storybook-prs/4111 to see this build running in a browser.

[Faye (Faye-Xiao)]

Found an issue that we still use the '@babel/preset-flow', we can't uninstall it right now. We need to finish ts migration first.