test: cover OTel metrics ForceFlush and Shutdown

[bm1549]

Motivation

Datadog's OTel metrics lifecycle support needs shared provider-level coverage without relying on process-exit hooks.

Changes

• Prove force_flush and shutdown export one exact pending DELTA metric before returning.
• Keep coverage enabled for Python, Go, Ruby, and Rust, whose existing public providers pass both tests.
• Activate Java from v1.66.0 and Node.js from v7.0.0 for their Datadog lifecycle extensions.
• Keep .NET excluded because it has no public provider shutdown; C++ and PHP retain file-level exclusions.
• Use a one-hour periodic interval, bounded provider and HTTP calls, forced process termination, and one final intake snapshot. The tests contain no sleeps or polling.

Live runs passed 2/2 on Python 4.14.0, Go 2.10.1, Ruby 2.42.0, and Rust 0.5.2. Java 1.65.1 and Node.js 6.13.0 confirmed their release gates.

Companion PRs: Java #12317, Node.js #10023, and documentation #39515.

Workflow

1. ⚠️ Create your PR as draft ⚠️
2. Work on your PR until CI passes.
3. Mark it ready for review.
   • Test logic is modified: get a review from the RFC owner.
   • Framework or non-obvious usage is modified: get a review from R&P.

Reviewer checklist

• Anything outside tests/ or manifests/ is modified: R&P approval is required.
• No Docker base image is modified.
• No scenario is added, removed, or renamed.

[github-actions]

CODEOWNERS have been resolved as:

manifests/dotnet.yml                                                    @DataDog/system-tests-reviewers
manifests/golang.yml                                                    @DataDog/system-tests-reviewers
manifests/java.yml                                                      @DataDog/system-tests-reviewers
manifests/nodejs.yml                                                    @DataDog/system-tests-reviewers
tests/parametric/test_otel_metrics.py                                   @DataDog/system-tests-core @DataDog/apm-sdk-capabilities
utils/build/docker/golang/parametric/helpers.go                         @DataDog/system-tests-reviewers
utils/build/docker/golang/parametric/main.go                            @DataDog/system-tests-reviewers
utils/build/docker/golang/parametric/otel_metrics.go                    @DataDog/system-tests-reviewers
utils/build/docker/java/parametric/src/main/java/com/datadoghq/trace/opentelemetry/controller/OpenTelemetryMetricsController.java  @DataDog/system-tests-reviewers
utils/build/docker/java/parametric/src/main/java/com/datadoghq/trace/opentelemetry/dto/FlushArgs.java  @DataDog/system-tests-reviewers
utils/build/docker/nodejs/parametric/server.js                          @DataDog/system-tests-reviewers
utils/build/docker/python/parametric/apm_test_client/server.py          @DataDog/system-tests-reviewers
utils/build/docker/ruby/parametric/server.rb                            @DataDog/system-tests-reviewers
utils/build/docker/rust/parametric/src/opentelemetry/mod.rs             @DataDog/system-tests-reviewers
utils/docker_fixtures/_test_clients/_test_client_parametric.py          @DataDog/system-tests-core

[datadog-official]

✅ All CI checks and tests passed.

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

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[mabdinur]

Reviewed the deterministic lifecycle validation and SDK adapters. CI is green.