Bump @testing-library/jest-dom from 5.17.0 to 6.4.6 in /webapp

Bumps [@testing-library/jest-dom](https://github.com/testing-library/jest-dom) from 5.17.0 to 6.4.6.
- [Release notes](https://github.com/testing-library/jest-dom/releases)
- [Changelog](https://github.com/testing-library/jest-dom/blob/main/CHANGELOG.md)
- [Commits](testing-library/jest-dom@v5.17.0...v6.4.6)

---
updated-dependencies:
- dependency-name: "@testing-library/jest-dom"
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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