Bump @next/mdx from 15.1.7 to 15.2.1

Bumps [@next/mdx](https://github.com/vercel/next.js/tree/HEAD/packages/next-mdx) from 15.1.7 to 15.2.1.
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](https://github.com/vercel/next.js/commits/v15.2.1/packages/next-mdx)

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

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -26,7 +26,7 @@
     "@liveblocks/react": "^2.16.2",
     "@mdx-js/loader": "^3.1.0",
     "@mdx-js/react": "^3.1.0",
-    "@next/mdx": "^15.1.6",
+    "@next/mdx": "^15.2.1",
     "@prisma/client": "^6.4.1",
     "@prisma/extension-accelerate": "^1.2.2",
     "@radix-ui/react-accordion": "^1.2.2",