Bump protobuf from 5.28.0 to 5.28.2 in /test (#681)

Bumps [protobuf](https://github.com/protocolbuffers/protobuf) from 5.28.0 to 5.28.2.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/protobuf_release.bzl)
- [Commits](protocolbuffers/protobuf@v5.28.0...v5.28.2)

---
updated-dependencies:
- dependency-name: protobuf
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

test/requirements.ci.txt

@@ -1,6 +1,6 @@
 docker==7.1.0
 grpcio==1.66.1
-protobuf==5.28.0
+protobuf==5.28.2
 requests==2.32.3
 urllib3==2.2.2
 websocket-client==1.8.0