GraphQL: Report multiple query errors

[marcotc]

Captures GraphQL error information as span events:

This is necessary because each query can have multiple errors (GraphQL spec for the "errors" field), which cannot reported using span tags (span tags only support one error per span).

Change log entry
GraphQL query errors are now reported as Span Events. This includes support for multiple errors, if present.

How to test the change?
All changes have unit tests and system-tests: DataDog/system-tests#3840

[datadog-datadog-prod-us1]

Datadog Report

Branch report: graphql-error-event
Commit report: a5b863e
Test service: dd-trace-rb

✅ 0 Failed, 22066 Passed, 1476 Skipped, 5m 30.76s Total Time

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 98.38710% with 1 line in your changes missing coverage. Please review.

Project coverage is 97.68%. Comparing base (4e27ecd) to head (91a93c6).

Files with missing lines	Patch %	Lines
...cing/contrib/graphql/support/application_schema.rb	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4177      +/-   ##
==========================================
- Coverage   97.69%   97.68%   -0.02%     
==========================================
  Files        1352     1352              
  Lines       82735    82785      +50     
  Branches     4200     4204       +4     
==========================================
+ Hits        80829    80869      +40     
- Misses       1906     1916      +10     

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[pr-commenter]

Benchmarks

Benchmark execution time: 2025-02-14 00:41:44

Comparing candidate commit 91a93c6 in PR branch graphql-error-event with baseline commit 4e27ecd in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 31 metrics, 2 unstable metrics.

[github-actions]

👋 Hey @marcotc, please fill "Change log entry" section in the pull request description.

If changes need to be present in CHANGELOG.md you can state it this way

**Change log entry**

Yes. A brief summary to be placed into the CHANGELOG.md

(possible answers Yes/Yep/Yeah)

Or you can opt out like that

**Change log entry**

None.

(possible answers No/Nope/None)

^{Visited at: 2025-01-18 00:02:08 UTC}

[datadog-datadog-prod-us1]

Datadog Report

Branch report: graphql-error-event
Commit report: 91a93c6
Test service: dd-trace-rb

✅ 0 Failed, 20107 Passed, 1360 Skipped, 3m 19.65s Total Time

[brett0000FF]

Approving docs change. Thanks!

[ivoanjo]

👍 LGTM! Looks pretty slick!