build(deps): bump fastify

Bumps the npm_and_yarn group with 1 update in the /services/user-service directory: [fastify](https://github.com/fastify/fastify).


Updates `fastify` from 5.8.1 to 5.8.4
- [Release notes](https://github.com/fastify/fastify/releases)
- [Commits](https://github.com/fastify/fastify/compare/v5.8.1...v5.8.4)

---
updated-dependencies:
- dependency-name: fastify
  dependency-version: 5.8.4
  dependency-type: direct:production
  dependency-group: npm_and_yarn
...

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

services/user-service/package.json

@@ -20,7 +20,7 @@
     "@connectrpc/connect-fastify": "^2.1.1",
     "@connectrpc/protoc-gen-connect-es": "^0.13.2",
     "@types/mongoose-unique-validator": "^1.0.7",
-    "fastify": "^5.8.1",
+    "fastify": "^5.8.4",
     "kafkajs": "^2.2.4",
     "mongoose": "^7.8.6",
     "mongoose-unique-validator": "^4.0.0",