Bump @mui/lab from 5.0.0-alpha.173 to 6.0.0-beta.9

Bumps [@mui/lab](https://github.com/mui/material-ui/tree/HEAD/packages/mui-lab) from 5.0.0-alpha.173 to 6.0.0-beta.9.
- [Release notes](https://github.com/mui/material-ui/releases)
- [Changelog](https://github.com/mui/material-ui/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mui/material-ui/commits/HEAD/packages/mui-lab)

---
updated-dependencies:
- dependency-name: "@mui/lab"
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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