fix(profiling): ensure correct thread link

[P403n1x87]

We use the C API to retrieve the thread ID of the current thread to create a link between threads and objects. This way we protect ourselves from frameworks such as gevent that might turn thread IDs into task IDs.

Testing strategy

Tested with a sample application that the endpoint information is attached to profiles with this change.

Checklist

• Change(s) are motivated and described in the PR description.
• Testing strategy is described if automated tests are not included in the PR.
• Risk is outlined (performance impact, potential for breakage, maintainability, etc).
• Change is maintainable (easy to change, telemetry, documentation).
• Library release note guidelines are followed. If no release note is required, add label changelog/no-changelog.
• Documentation is included (in-code, generated user docs, public corp docs).
• Backport labels are set (if applicable)

Reviewer Checklist

• Title is accurate.
• No unnecessary changes are introduced.
• Description motivates each change.
• Avoids breaking API changes unless absolutely necessary.
• Testing strategy adequately addresses listed risk(s).
• Change is maintainable (easy to change, telemetry, documentation).
• Release note makes sense to a user of the library.
• Reviewer has explicitly 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
• If this PR touches code that signs or publishes builds or packages, or handles credentials of any kind, I've requested a review from @DataDog/security-design-and-guidance.
• This PR doesn't touch any of that.

[sanchda]

I have one concern, but if you feel it isn't an issue, everything else looks good to me.

[github-actions]

The backport to 1.17 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-1.17 1.17
# Navigate to the new working tree
cd .worktrees/backport-1.17
# Create a new branch
git switch --create backport-6798-to-1.17
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 827f553373d988b547913c827ed813b52ec9a119
# Push it to GitHub
git push --set-upstream origin backport-6798-to-1.17
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-1.17

Then, create a pull request where the base branch is 1.17 and the compare/head branch is backport-6798-to-1.17.