Bump @mui/material from 5.13.4 to 5.16.6 in /client/StichHub

Bumps [@mui/material](https://github.com/mui/material-ui/tree/HEAD/packages/mui-material) from 5.13.4 to 5.16.6.
- [Release notes](https://github.com/mui/material-ui/releases)
- [Changelog](https://github.com/mui/material-ui/blob/v5.16.6/CHANGELOG.md)
- [Commits](https://github.com/mui/material-ui/commits/v5.16.6/packages/mui-material)

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

Signed-off-by: dependabot[bot] <[email protected]>