fix(llmobs): don't enqueue spans to an inactive evaluator runner [backport 2.17]

[lievan]

backports #12150

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-evaluator-runner-log-fcd0aa18602d4252.yaml       @DataDog/apm-python
ddtrace/llmobs/_evaluators/runner.py                                    @DataDog/ml-observability
tests/llmobs/test_llmobs_evaluator_runner.py                            @DataDog/ml-observability
tests/llmobs/test_llmobs_service.py                                     @DataDog/ml-observability

[datadog-dd-trace-py-rkomorn]

Datadog Report

Branch report: evan.li/backport-12150-2.17
Commit report: a8ab88e
Test service: dd-trace-py

✅ 0 Failed, 1286 Passed, 0 Skipped, 30m 48.34s Total duration (7m 45.45s time saved)

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-02-03 16:58:34

Comparing candidate commit 8d4b9a4 in PR branch evan.li/backport-12150-2.17 with baseline commit 87ce8ad in branch 2.17.

Found 0 performance improvements and 3 performance regressions! Performance is the same for 385 metrics, 2 unstable metrics.

scenario:iast_aspects-ospathnormcase_aspect

• 🟥 execution_time [+253.880ns; +296.631ns] or [+9.899%; +11.566%]

scenario:iast_aspects-splitlines_aspect

• 🟥 execution_time [+141.086ns; +170.411ns] or [+8.042%; +9.714%]

scenario:iast_aspects-translate_aspect

• 🟥 execution_time [+289.603ns; +330.221ns] or [+7.412%; +8.451%]