Bump node-notifier and jest in /packages/koa-signal

Removes [node-notifier](https://github.com/mikaelbr/node-notifier). It's no longer used after updating ancestor dependency [jest](https://github.com/jestjs/jest/tree/HEAD/packages/jest). These dependencies need to be updated together.


Removes `node-notifier`

Updates `jest` from 24.9.0 to 29.6.4
- [Release notes](https://github.com/jestjs/jest/releases)
- [Changelog](https://github.com/jestjs/jest/blob/main/CHANGELOG.md)
- [Commits](https://github.com/jestjs/jest/commits/v29.6.4/packages/jest)

---
updated-dependencies:
- dependency-name: node-notifier
  dependency-type: indirect
- dependency-name: jest
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>