chore(deps): bump @mui/material in /packages/web-app

Bumps [@mui/material](https://github.com/mui/material-ui/tree/HEAD/packages/mui-material) from 5.16.8 to 6.1.9.
- [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/v6.1.9/packages/mui-material)

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

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

packages/web-app/package.json

@@ -16,7 +16,7 @@
     "@emotion/styled": "^11.13.0",
     "@mui/icons-material": "^5.16.7",
     "@mui/lab": "^5.0.0-alpha.173",
-    "@mui/material": "^5.16.7",
+    "@mui/material": "^6.1.9",
     "@mui/styles": "^5.16.7",
     "@mui/x-date-pickers": "^7.19.0",
     "@react-leaflet/core": "2.1.0",