feat: iast execute source metric

[avara1986]

• Attach execute source in the span metrics
• Refactor IAST span metrics to use iast context instead of a global variable

Checklist

• [x] 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

• [x] 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[bot]]

CODEOWNERS have been resolved as:

ddtrace/appsec/_constants.py                                            @DataDog/asm-python
ddtrace/appsec/_iast/_iast_request_context.py                           @DataDog/asm-python
ddtrace/appsec/_iast/_metrics.py                                        @DataDog/asm-python
ddtrace/appsec/_iast/_taint_tracking/__init__.py                        @DataDog/asm-python
tests/appsec/iast/test_telemetry.py                                     @DataDog/asm-python

[pr-commenter[bot]]

Benchmarks

Benchmark execution time: 2024-11-20 16:23:29

Comparing candidate commit 98f1fdf56eee442e78393f3cdc1bb430f4d0d396 in PR branch avara1986/APPSEC-55759-telemetry_execute_metric with baseline commit c26fd4c9dffa1c8f083db729462d2b2286c60ddb in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 388 metrics, 2 unstable metrics.