test(parametric): make OTel span assertions v0.4/v1-agnostic.

[AlexeyKuznetsov-DD]

What Does This Do

Makes the parametric OTel span and span-event assertions protocol-agnostic for trace payloads that may arrive in either v0.4-style or v1.0-style shapes.

• Adds is_same_boolean(..., is_otel_boolean=True) support for comparing boolean values represented as "true"/"false", native True/False, or OTel numeric 1/0.
• Updates OTel span tests to read boolean attributes from merged meta/metrics data and to tolerate empty optional tracestate/attributes fields.
• Uses retrieve_span_events() in span event tests instead of directly parsing span["meta"]["events"].
• Extends native span-event attribute flattening so protocol v1 array attributes become plain Python lists.
• Adds TEST_THE_TEST coverage for the boolean comparison helper.

Motivation

dd-trace-java protocol v1 span events serialize some OTel data differently from older trace formats. These changes keep the shared parametric assertions focused on behavior instead of the exact wire-format representation used by a tracer/protocol combination.

[datadog-datadog-prod-us1]

🎉 All green!

🧪 All tests passed
❄️ No new flaky tests detected

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[github-actions]

CODEOWNERS have been resolved as:

tests/test_the_test/test_dd_types.py                                    @DataDog/system-tests-core
tests/parametric/test_otel_span_methods.py                              @DataDog/system-tests-core @DataDog/apm-sdk-capabilities
tests/parametric/test_span_events.py                                    @DataDog/system-tests-core @DataDog/apm-sdk-capabilities
tests/test_the_test/scenarios.json                                      @DataDog/system-tests-core
utils/dd_types/_utils.py                                                @DataDog/system-tests-core
utils/docker_fixtures/spec/trace.py                                     @DataDog/system-tests-core