chore(deps-dev): bump @testing-library/react in /assets

Bumps [@testing-library/react](https://github.com/testing-library/react-testing-library) from 11.2.7 to 12.1.5.
- [Release notes](https://github.com/testing-library/react-testing-library/releases)
- [Changelog](https://github.com/testing-library/react-testing-library/blob/main/CHANGELOG.md)
- [Commits](testing-library/react-testing-library@v11.2.7...v12.1.5)

---
updated-dependencies:
- dependency-name: "@testing-library/react"
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>