build(deps-dev): bump happy-dom from 14.12.3 to 15.7.4 in /frontend

Bumps [happy-dom](https://github.com/capricorn86/happy-dom) from 14.12.3 to 15.7.4.
- [Release notes](https://github.com/capricorn86/happy-dom/releases)
- [Commits](capricorn86/happy-dom@v14.12.3...v15.7.4)

---
updated-dependencies:
- dependency-name: happy-dom
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

frontend/package.json

@@ -126,7 +126,7 @@
     "eslint-plugin-vuetify": "^2.4.0",
     "eslint-plugin-yml": "^1.14.0",
     "fs-extra": "^11.2.0",
-    "happy-dom": "^14.12.3",
+    "happy-dom": "^15.7.4",
     "mock-apollo-client": "^1.3.1",
     "prettier": "^3.3.3",
     "react": "^18.3.1",