refactor: Move OtlpPayload and OTLP request bodies to communication/otlp-exporter

[jbachorik]

What Does This Do

Moves OtlpPayload, OtlpHttpRequestBody, and OtlpGrpcRequestBody and their two tests from dd-trace-core to the new module communication/otlp-exporter. The moved files change only their package line. The rest of the change is import updates in dd-trace-core and the module setup: settings, build files, muzzle filter, agent shadow jar, and CODEOWNERS.

Motivation

The profiler sends profiles through the same OTLP transport as the tracer. The profiler modules depend on communication and internal-api, but not on dd-trace-core. The transport code must therefore live outside dd-trace-core.

This PR moves the payload and the request body classes. The sender classes follow in the next PR, together with the response type change they need.

Additional Notes

Part of a 5-PR stack. Each PR bases on the previous one.

1. this PR: the payload and request body move
2. OTLP sender extraction and canonical resource attributes (refactor: Extract OTLP sender infrastructure to communication/otlp-exporter #12868)
3. RecordingData reference counting (feat(profiling): Reference-count RecordingData lifecycle #12869)
4. JFR to OTLP/P converter, profiling-otel, plus jafar 0.26.2 (feat(profiling): Add JFR to OTLP/P converter with CLI, benchmarks and validation #12870)
5. OTLP profiles export wiring (feat(profiling): Integrate OTLP profiles export into the agent #12871)

Contributor Checklist

• Format the title according to the contribution guidelines
• Assign the type: and (comp: or inst:) labels in addition to any other useful labels
• Update the CODEOWNERS file on source file addition, migration, or deletion
• Update public documentation with any new configuration flags or behaviors
• Once approved, use merge queue to merge the PR

Jira ticket: [PROJ-IDENT]

[dd-octo-sts]

🟢 Java Benchmark SLOs — All performance SLOs passed

Suite	Status
Startup	🟢 pass

SLO thresholds are defined here based on automatically generated metrics. A warning is raised when results are within 5% of the threshold.

PR vs. master results

Scenario	Candidate	master	Δ (95% CI of mean)
startup:insecure-bank:iast:Agent	14.76 s	14.60 s	[+0.3%; +1.9%] (maybe worse)
startup:insecure-bank:tracing:Agent	13.59 s	13.58 s	[-0.8%; +0.9%] (no difference)
startup:petclinic:appsec:Agent	17.60 s	17.42 s	[+0.1%; +2.0%] (maybe worse)
startup:petclinic:iast:Agent	17.30 s	17.43 s	[-1.7%; +0.1%] (no difference)
startup:petclinic:profiling:Agent	17.30 s	16.66 s	[-0.6%; +8.3%] (no difference)
startup:petclinic:sca:Agent	17.66 s	16.96 s	[-0.5%; +8.7%] (no difference)
startup:petclinic:tracing:Agent	16.52 s	16.20 s	[-2.2%; +6.2%] (no difference)

Commit: 73a86956 · CI Pipeline · Benchmarking Platform UI

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Load and DaCapo benchmarks can be triggered manually in the GitLab pipeline. Results will appear in the Benchmarking Platform UI after completion.