Bump next from 15.2.3 to 15.4.7 in /create-leo-app/template-nextjs-ts

Bumps [next](https://github.com/vercel/next.js) from 15.2.3 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@v15.2.3...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]

create-leo-app/template-nextjs-ts/package.json

@@ -10,7 +10,7 @@
   },
   "dependencies": {
     "@provablehq/sdk": "^0.9.8",
-    "next": "15.2.3",
+    "next": "15.4.7",
     "react": "^19.0.0",
     "react-dom": "^19.0.0",
     "terser-webpack-plugin": "^5.3.11"