Bump fastify from 4.28.1 to 5.2.1

Bumps [fastify](https://github.com/fastify/fastify) from 4.28.1 to 5.2.1.
- [Release notes](https://github.com/fastify/fastify/releases)
- [Commits](fastify/fastify@v4.28.1...v5.2.1)

---
updated-dependencies:
- dependency-name: fastify
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

apps/backend/package.json

@@ -38,7 +38,7 @@
     "@prisma/client": "5.22.0",
     "auth0": "4.14.0",
     "dotenv": "16.4.5",
-    "fastify": "4.28.1",
+    "fastify": "5.2.1",
     "graphql": "16.9.0",
     "graphql-scalars": "1.24.0",
     "jsonwebtoken": "9.0.2",