Add scenario to test client_drop_p0s set to false

[ichinaski]

Motivation

Add a new scenario to test the combination of Client-Side Stats alongside client_drop_p0s set to false on the trace-agent (for example, when Probabilistic Sampler is enaabled).

A recent bug on dd-trace-go revealed that this setting may not be correctly used. This is now fixed.

Changes

Add new scenario and test.

Workflow

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

🚀 Once your PR is reviewed and the CI green, you can merge it!

🛟 #apm-shared-testing 🛟

Reviewer checklist

• Anything but tests/ or manifests/ is modified ? I have the approval from R&P team
• A docker base image is modified?
  • the relevant build-XXX-image label is present
• A scenario is added, removed or renamed?
  • Get a review from R&P team

[github-actions]

CODEOWNERS have been resolved as:

manifests/cpp.yml                                                       @DataDog/dd-trace-cpp
manifests/cpp_httpd.yml                                                 @DataDog/system-tests-core
manifests/cpp_nginx.yml                                                 @DataDog/system-tests-core
manifests/dotnet.yml                                                    @DataDog/apm-dotnet @DataDog/asm-dotnet
manifests/golang.yml                                                    @DataDog/dd-trace-go-guild
manifests/java.yml                                                      @DataDog/asm-java @DataDog/apm-java
manifests/nodejs.yml                                                    @DataDog/dd-trace-js
manifests/php.yml                                                       @DataDog/apm-php @DataDog/asm-php
manifests/python.yml                                                    @DataDog/apm-python @DataDog/asm-python
manifests/ruby.yml                                                      @DataDog/ruby-guild @DataDog/asm-ruby
manifests/rust.yml                                                      @DataDog/apm-rust
tests/stats/test_stats.py                                               @DataDog/system-tests-core
utils/_context/_scenarios/__init__.py                                   @DataDog/system-tests-core
utils/_context/_scenarios/endtoend.py                                   @DataDog/system-tests-core
utils/_context/containers.py                                            @DataDog/system-tests-core
utils/proxy/mocked_response.py                                          @DataDog/system-tests-core

[VianneyRuhlmann]

LGTM