fix(deps): update dependency @next/mdx to v16

Author: renovate[bot]

package.json

@@ -14,7 +14,7 @@
     "e2e": "playwright test"
   },
   "dependencies": {
-    "@next/mdx": "15.5.11",
+    "@next/mdx": "16.1.6",
     "motion": "^10.18.0",
     "next": "16.1.5",
     "normalize.css": "8.0.1",