Bump xmldom and lighthouse

Removes [xmldom](https://github.com/xmldom/xmldom). It's no longer used after updating ancestor dependency [lighthouse](https://github.com/GoogleChrome/lighthouse). These dependencies need to be updated together.


Removes `xmldom`

Updates `lighthouse` from 5.6.0 to 9.6.8
- [Release notes](https://github.com/GoogleChrome/lighthouse/releases)
- [Changelog](https://github.com/GoogleChrome/lighthouse/blob/v9.6.8/changelog.md)
- [Commits](GoogleChrome/lighthouse@v5.6.0...v9.6.8)

---
updated-dependencies:
- dependency-name: xmldom
  dependency-type: indirect
- dependency-name: lighthouse
  dependency-type: direct:development
...

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