Bump @testing-library/jest-dom from 6.4.6 to 6.4.8 in the testing group

Bumps the testing group with 1 update: [@testing-library/jest-dom](https://github.com/testing-library/jest-dom).


Updates `@testing-library/jest-dom` from 6.4.6 to 6.4.8
- [Release notes](https://github.com/testing-library/jest-dom/releases)
- [Changelog](https://github.com/testing-library/jest-dom/blob/main/CHANGELOG.md)
- [Commits](https://github.com/testing-library/jest-dom/compare/v6.4.6...v6.4.8)

---
updated-dependencies:
- dependency-name: "@testing-library/jest-dom"
  dependency-type: direct:development
  update-type: version-update:semver-patch
  dependency-group: testing
...

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

package.json

@@ -60,7 +60,7 @@
     "@shlinkio/eslint-config-js-coding-standard": "~3.0.0",
     "@shlinkio/stylelint-config-css-coding-standard": "~1.1.1",
     "@stylistic/eslint-plugin": "^2.3.0",
-    "@testing-library/jest-dom": "^6.4.6",
+    "@testing-library/jest-dom": "^6.4.8",
     "@testing-library/react": "^16.0.0",
     "@testing-library/user-event": "^14.5.2",
     "@total-typescript/shoehorn": "^0.1.2",