chore(deps): bump ajv and fastify in /packages/server

Bumps [ajv](https://github.com/ajv-validator/ajv) to 8.18.0 and updates ancestor dependency [fastify](https://github.com/fastify/fastify). These dependencies need to be updated together.


Updates `ajv` from 6.12.6 to 8.18.0
- [Release notes](https://github.com/ajv-validator/ajv/releases)
- [Commits](ajv-validator/ajv@v6.12.6...v8.18.0)

Updates `fastify` from 3.27.4 to 5.7.4
- [Release notes](https://github.com/fastify/fastify/releases)
- [Commits](fastify/fastify@v3.27.4...v5.7.4)

---
updated-dependencies:
- dependency-name: ajv
  dependency-version: 8.18.0
  dependency-type: indirect
- dependency-name: fastify
  dependency-version: 5.7.4
  dependency-type: direct:production
...

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Author: dependabot[bot]