fix(sampling): validate_sampling_decision giving log warns on supported mechanisms

[bqbits]

#13516

https://gitlab.ddbuild.io/DataDog/apm-reliability/dd-trace-py/-/jobs/961877338#L460
=========================== short test summary info ============================
FAILED tests/integration/test_sampling.py::test_supported_sampling_mechanism - AssertionError: DATA_JOBS_MONITORING returned {'_dd.propagation_error': 'decoding_error'}
assert {'_dd.propagation_error': 'decoding_error'} != {'_dd.propagation_error': 'decoding_error'}
====== 1 failed, 104 passed, 28 skipped, 6 xpassed, 14 warnings in 26.31s ======
Test failed with exit code 1

Checklist

• PR author has checked that all the criteria below are met
• The PR description includes an overview of the change
• The PR description articulates the motivation for the change
• The change includes tests OR the PR description describes a testing strategy
• The PR description notes risks associated with the change, if any
• Newly-added code is easy to change
• The change follows the library release note guidelines
• The change includes or references documentation updates if necessary
• Backport labels are set (if applicable)

Reviewer Checklist

• Reviewer has checked that all the criteria below are met
• Title is accurate
• All changes are related to the pull request's stated goal
• Avoids breaking API changes
• Testing strategy adequately addresses listed risks
• Newly-added code is easy to change
• Release note makes sense to a user of the library
• If necessary, author has acknowledged and discussed the performance implications of this PR as reported in the benchmarks PR comment
• Backport labels are set in a manner that is consistent with the release branch maintenance policy

[github-actions]

CODEOWNERS have been resolved as:

releasenotes/notes/fix-validate-sampling-decision-logging-561e2ef1c0156b5e.yaml  @DataDog/apm-python
ddtrace/internal/sampling.py                                            @DataDog/apm-sdk-api-python
tests/integration/test_sampling.py                                      @DataDog/apm-core-python
tests/tracer/test_propagation.py                                        @DataDog/apm-sdk-api-python

[github-actions]

Bootstrap import analysis

Comparison of import times between this PR and base.

Summary

The average import time from this PR is: 245 ± 3 ms.

The average import time from base is: 247 ± 2 ms.

The import time difference between this PR and base is: -1.6 ± 0.1 ms.

Import time breakdown

The following import paths have shrunk:

ddtrace.auto 2.042 ms (0.83%)

ddtrace.bootstrap.sitecustomize 1.301 ms (0.53%)

ddtrace.bootstrap.preload 1.301 ms (0.53%)

ddtrace.internal.remoteconfig.client 0.639 ms (0.26%)

ddtrace 0.741 ms (0.30%)

ddtrace.trace 0.064 ms (0.03%)

ddtrace._trace.filters 0.064 ms (0.03%)

ddtrace._trace.processor 0.064 ms (0.03%)

ddtrace._trace.sampler 0.064 ms (0.03%)

ddtrace._trace.span 0.064 ms (0.03%)

ddtrace.internal.sampling 0.064 ms (0.03%)

ddtrace.internal._unpatched 0.026 ms (0.01%)

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-06-03 20:11:33

Comparing candidate commit dbb575c in PR branch benson-branch with baseline commit 22ded2c in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 497 metrics, 3 unstable metrics.

[github-actions]

The backport to 2.21 failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-2.21 2.21
# Navigate to the new working tree
cd .worktrees/backport-2.21
# Create a new branch
git switch --create backport-13554-to-2.21
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 733711e80245610dfd3af221fb9b3f32b6a3ff97
# Push it to GitHub
git push --set-upstream origin backport-13554-to-2.21
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-2.21

Then, create a pull request where the base branch is 2.21 and the compare/head branch is backport-13554-to-2.21.