fix: fix trace id in logs when using set_parent nested in a trace span

[SF-Zhou]

Fixes #2824.

Changes

When using distributed tracing and calling set_parent to set the context, the currently obtained trace_id was incorrect. This PR fixes this issue.

This fix has been validated in online production environments. For users with the same requirements, they can temporarily opt to use the patched opentelemetry-appender-tracing-patched crate.

Merge requirement checklist

• CONTRIBUTING guidelines followed
• Unit tests added/updated (if applicable)
• Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

Attention: Patch coverage is 98.27586% with 1 line in your changes missing coverage. Please review.

Project coverage is 81.2%. Comparing base (bf22aeb) to head (ad031b8).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
opentelemetry-appender-tracing/src/layer.rs	98.2%	1 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #2924   +/-   ##
=====================================
  Coverage   81.1%   81.2%           
=====================================
  Files        126     126           
  Lines      24794   24839   +45     
=====================================
+ Hits       20131   20173   +42     
- Misses      4663    4666    +3     

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[scottgerring]

Hey @SF-Zhou thanks for opening the PR!
Can you give a few more details on what exactly led to this?

[SF-Zhou]

Hey @SF-Zhou thanks for opening the PR! Can you give a few more details on what exactly led to this?

Sure. The description of the PR has been updated.

[scottgerring]

@bantonsson I think your eyes on this would be helpful!

[cijothomas]

Thanks!

Requesting changing to address the comment below:
See https://github.com/open-telemetry/opentelemetry-rust/pull/2924/files#r2044837776

[SF-Zhou]

Thanks!

Requesting changing to address the comment below: See https://github.com/open-telemetry/opentelemetry-rust/pull/2924/files#r2044837776

Done.

[SF-Zhou]

@cijothomas could you please review the updates when convenient? If everything looks good, we can proceed to merge.

Concerning change was reverted, thanks!