chore: bump protobuf from 6.32.1 to 6.33.5 in /services/rag-backend

Bumps [protobuf](https://github.com/protocolbuffers/protobuf) from 6.32.1 to 6.33.5.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Commits](https://github.com/protocolbuffers/protobuf/commits)

---
updated-dependencies:
- dependency-name: protobuf
  dependency-version: 6.33.5
  dependency-type: indirect
...

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Author: dependabot[bot]