fix(llmobs): don't drop IO annotations equal to zero (#11044) [backport 2.12]

[lievan]

Backport 2f23eb2 from #11044 to 2.12.

Fixes an issue where we are dropping I/O annotations that were equal to zero for workflow, task, agent and tool spans.

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• Avoids breaking API changes

• Testing strategy adequately addresses listed risks

• Newly-added code is easy to change

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• Backport labels are set in a manner that is consistent with the release branch maintenance
  policy

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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

[datadog-dd-trace-py-rkomorn]

Datadog Report

Branch report: evan.li/backport-11044-2.12
Commit report: c8f38ba
Test service: dd-trace-py

✅ 0 Failed, 6363 Passed, 34564 Skipped, 35m 55.36s Total duration (1h 51m 57.61s time saved)

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-10-28 14:56:31

Comparing candidate commit c8f38ba in PR branch evan.li/backport-11044-2.12 with baseline commit 539f2c3 in branch 2.12.

Found 1 performance improvements and 0 performance regressions! Performance is the same for 353 metrics, 46 unstable metrics.

scenario:span-start

• 🟩 max_rss_usage [-4.102MB; -4.020MB] or [-10.500%; -10.288%]