Bump protobuf in /release/smoke-tests/otel-span-exporter

Bumps [protobuf](https://github.com/protocolbuffers/protobuf) from 3.19.5 to 4.25.8.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/protobuf_release.bzl)
- [Commits](protocolbuffers/protobuf@v3.19.5...v4.25.8)

---
updated-dependencies:
- dependency-name: protobuf
  dependency-version: 4.25.8
  dependency-type: direct:production
...

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

Author: dependabot[bot]

release/smoke-tests/otel-span-exporter/requirements.txt

@@ -12,7 +12,7 @@ opentelemetry-exporter-otlp-proto-http==1.25.0
 opentelemetry-proto==1.25.0
 opentelemetry-sdk==1.25.0
 opentelemetry-semantic-conventions==0.46b0
-protobuf==3.19.5
+protobuf==4.25.8
 requests==2.32.3
 six==1.16.0
 urllib3==1.26.19