Bump happy-dom from 20.1.0 to 20.8.9 in /nifi-frontend/src/main/frontend

Bumps [happy-dom](https://github.com/capricorn86/happy-dom) from 20.1.0 to 20.8.9.
- [Release notes](https://github.com/capricorn86/happy-dom/releases)
- [Commits](capricorn86/happy-dom@v20.1.0...v20.8.9)

---
updated-dependencies:
- dependency-name: happy-dom
  dependency-version: 20.8.9
  dependency-type: direct:development
...

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