test(dotnet): revert easywins for OtelTracestate sampling, disable IAST in sampling scenario

[MilanGarnier]

These were activated by easy win script but some will be marked as bug
Moreover, IAST flags the payload in make_distant_call and makes a force keeps which would break the test in python, dotnet, Java and PHP. Action: move the impacted test to the sampling scenario, and restrict the a SamplingTest to its own spans (because the moved test involve manual keep)

Summary

• disable the .NET parametric and end-to-end OTel tracestate sampling suites
• run every end-to-end OTel tracestate test in SAMPLING instead of DEFAULT
• disable AppSec and IAST in the SAMPLING scenario
• remove only the OTel tracestate activations introduced by the automated easy-win PR

All .NET declarations retain the APMAPI-2171 missing-feature marker.

[github-actions]

CODEOWNERS have been resolved as:

manifests/dotnet.yml                                                    @DataDog/system-tests-reviewers
tests/test_otel_tracestate_sampling.py                                  @DataDog/system-tests-core
tests/test_sampling_rates.py                                            @DataDog/system-tests-core
utils/_context/_scenarios/__init__.py                                   @DataDog/system-tests-core

[datadog-datadog-prod-us1]

 

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[MilanGarnier]

Tried to use decision maker (checking manual keep), but dd-trace-dotnet does not emit it for the root span so I fall back on limiting the scope to the spans emitted for the test.

[MilanGarnier]

/merge -m squash

[gh-worker-devflow-routing-ef8351]

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2026-09-02 16:07:53 UTC ℹ️ Start processing command /merge -m squash

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