chore(iast): fix IAST imports when under pytest

[juanjux]

Description

PR #12198 had the unintended consequence of not honoring DD_IAST_ENABLED if set after the _common_module_patches.py was evaluated. This make some tests (ssrf and probably others) to not run. This fixes the problem by moving is_iast_request_enabled and _IAST_CONTEXT to asm_config.

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
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• 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]

CODEOWNERS have been resolved as:

ddtrace/appsec/_asm_request_context.py                                  @DataDog/asm-python
ddtrace/appsec/_common_module_patches.py                                @DataDog/asm-python
ddtrace/appsec/_constants.py                                            @DataDog/asm-python
ddtrace/appsec/_iast/_handlers.py                                       @DataDog/asm-python
ddtrace/appsec/_iast/_iast_request_context.py                           @DataDog/asm-python
ddtrace/appsec/_iast/_patches/json_tainting.py                          @DataDog/asm-python
ddtrace/appsec/_iast/_taint_tracking/_taint_objects.py                  @DataDog/asm-python
ddtrace/appsec/_iast/reporter.py                                        @DataDog/asm-python
ddtrace/appsec/_iast/taint_sinks/_base.py                               @DataDog/asm-python
ddtrace/appsec/_iast/taint_sinks/code_injection.py                      @DataDog/asm-python
ddtrace/appsec/_iast/taint_sinks/command_injection.py                   @DataDog/asm-python
ddtrace/appsec/_iast/taint_sinks/header_injection.py                    @DataDog/asm-python
ddtrace/appsec/_iast/taint_sinks/insecure_cookie.py                     @DataDog/asm-python
ddtrace/appsec/_iast/taint_sinks/path_traversal.py                      @DataDog/asm-python
ddtrace/appsec/_iast/taint_sinks/ssrf.py                                @DataDog/asm-python
ddtrace/appsec/_iast/taint_sinks/xss.py                                 @DataDog/asm-python
ddtrace/settings/asm.py                                                 @DataDog/asm-python

[pr-commenter]

Benchmarks

Benchmark execution time: 2025-02-14 13:58:51

Comparing candidate commit 03b0465 in PR branch juanjux/fix-iast-imports-in-pytests with baseline commit 05c9824 in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 394 metrics, 2 unstable metrics.

[juanjux]

Moving to draft, will be rewritten with a less clumsy implementation.