chore(deps): update @mui/material requirement in /src

Updates the requirements on [@mui/material](https://github.com/mui/material-ui/tree/HEAD/packages/mui-material) to permit the latest version.
- [Release notes](https://github.com/mui/material-ui/releases)
- [Changelog](https://github.com/mui/material-ui/blob/v5.15.21/CHANGELOG.md)
- [Commits](https://github.com/mui/material-ui/commits/v5.15.21/packages/mui-material)

---
updated-dependencies:
- dependency-name: "@mui/material"
  dependency-type: direct:production
...

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

src/package.json

@@ -6,7 +6,7 @@
         "@babel/plugin-proposal-private-property-in-object": "^7.21.11",
         "@iobroker/adapter-react-v5": "^6.0.9",
         "@mui/icons-material": "^5.15.20",
-        "@mui/material": "^5.15.20",
+        "@mui/material": "^5.15.21",
         "@sentry/browser": "^8.12.0",
         "babel-eslint": "^10.1.0",
         "eslint": "^8.57.0",