Fix batchProcessor to set correct span format flags

[k0zl]

Which problem is this PR solving?

Recently I've noticed that collector sends wrong tags "format" and "transport" in metric jaeger_collector_spans_received_total.

Root cause: when batchProcessor was extended to be called from OTLP Receiver, it was given SpanOptions parameter that could specify a different span format OTLP, vs. always setting Proto. But the processor was still using hardcoded Proto format when invoking the next processor.

How was this change tested?

Added unit test

Checklist

• [ x ] I have read https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
• [ x ] I have signed all commits
• [ - ] I have added unit tests for the new functionality (not needed)
• [ x ] I have run lint and test steps successfully
  • for jaeger: make lint test
  • for jaeger-ui: yarn lint and yarn test

[albertteoh]

Thanks! Please sign your commit.

[k0zl]

Thanks! Please sign your commit.

Yep, already did

[codecov]

Codecov Report

All modified lines are covered by tests ✅

Files	Coverage Δ
cmd/collector/app/handler/grpc_handler.go	100.00% <100.00%> (ø)

📢 Thoughts on this report? Let us know!.

[k0zl]

@albertteoh could you approve the required workflows please?

[yurishkuro]

please add unit test that illustrates the issue

[k0zl]

Added unit test

[yurishkuro]

Thanks!