Bump next from 15.2.4 to 15.4.7 in /dashboard

Bumps [next](https://github.com/vercel/next.js) from 15.2.4 to 15.4.7.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](vercel/next.js@v15.2.4...v15.4.7)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 15.4.7
  dependency-type: direct:production
...

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

Author: dependabot[bot]

dashboard/package.json

@@ -16,7 +16,7 @@
     "@mui/joy": "^5.0.0-beta.32",
     "@mui/material": "^5.15.14",
     "dayjs": "^1.11.10",
-    "next": "15.2.4",
+    "next": "15.4.7",
     "react": "^18",
     "react-dom": "^18",
     "swr": "^2.2.5"