fix(tracing): fix traceback max size for exceptions

[quiqueg]

#7558 made the traceback size configurable via DD_TRACE_SPAN_TRACEBACK_MAX_SIZE, but tracebacks for exceptions were still hardcoded with a limit of 30.

The fix is modeled after Span#set_traceback's existing logic, and tests were modeled after both test_traceback_with_error and test_custom_traceback_size. Not much new logic, just an edge case.

Checklist

• Change(s) are motivated and described in the PR description
• Testing strategy is described if automated tests are not included in the PR
• Risks are described (performance impact, potential for breakage, maintainability)
• Change is maintainable (easy to change, telemetry, documentation)
• Library release note guidelines are followed or label changelog/no-changelog is set
• Documentation is included (in-code, generated user docs, public corp docs)
• Backport labels are set (if applicable)
• If this PR changes the public interface, I've notified @DataDog/apm-tees.

Reviewer Checklist

• Title is accurate
• All changes are related to the pull request's stated goal
• Description motivates each change
• Avoids breaking API changes
• Testing strategy adequately addresses listed risks
• Change is maintainable (easy to change, telemetry, documentation)
• Release note makes sense to a user of the library
• 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

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 15.00000% with 17 lines in your changes are missing coverage. Please review.

Project coverage is 9.96%. Comparing base (f38dbd4) to head (40dc744).
Report is 2 commits behind head on main.

Files	Patch %	Lines
tests/tracer/test_span.py	0.00%	16 Missing ⚠️
ddtrace/_trace/span.py	75.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main    #9112       +/-   ##
===========================================
- Coverage   75.92%    9.96%   -65.96%     
===========================================
  Files        1296     1267       -29     
  Lines      123157   121468     -1689     
===========================================
- Hits        93507    12106    -81401     
- Misses      29650   109362    +79712     

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[quiqueg]

@erikayasuda @Kyle-Verhoog Gentle ping—could I please get a review on this when you have a moment? This is impacting our ability to properly track errors in our application via APM.

[quiqueg]

@erikayasuda Did you have any comments on the release note? I noticed that you left Release note makes sense to a user of the library unchecked in the reviewer checklist.

[quiqueg]

@erikayasuda This PR should be good to go. It looks like just the Library Injection / build-and-publish-test-image / build_push / build_push CI job is failing with a docker push 403 Unauthorized error. I'm not familiar with this project's CI setup, but it might be because my fork (as an outside contributor) doesn't have access to the secrets.GITHUB_TOKEN?

I don't have merge permissions in this repo, so please feel free to take over and merge when you have a chance to do so. Thank you!

[erikayasuda]

Hi @quiqueg , sorry for the slow cycles here. I just updated the branch, and enabled auto-merge, so that should merge today assuming the tests all go well. Thanks for the patience!

[quiqueg]

@erikayasuda Looks like the Library Injection / build-and-publish-test-image / build_push / build_push test is still failing with the same 403 Unauthorized error that I mentioned above. Could you please take a look?