fix: error parsing response cookies in FastAPI and awsgi

[avara1986]

This fix resolves an issue parsing response cookies in FastAPI and awsgi

issue: #11818

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
• 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]

CODEOWNERS have been resolved as:

releasenotes/notes/iast-fix-awsgi-368c173e1f012400.yaml                 @DataDog/apm-python
ddtrace/contrib/internal/asgi/middleware.py                             @DataDog/apm-core-python @DataDog/apm-idm-python
tests/contrib/asgi/test_asgi.py                                         @DataDog/apm-core-python @DataDog/apm-idm-python

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-12-24 12:43:05

Comparing candidate commit 7bef2fe in PR branch avara1986/fix_fastapi_cookies_parse with baseline commit 998ee2c in branch main.

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

[github-actions]

The backport to 2.16 failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-2.16 2.16
# Navigate to the new working tree
cd .worktrees/backport-2.16
# Create a new branch
git switch --create backport-11829-to-2.16
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 e29ccb0a68bc73bf3d7f071e66e1c8a20eb0c801
# Push it to GitHub
git push --set-upstream origin backport-11829-to-2.16
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-2.16

Then, create a pull request where the base branch is 2.16 and the compare/head branch is backport-11829-to-2.16.