fix: don't skip heartbeats for forked processes

[juanjux]

Description

We were skipping app-heartbeat messages for forked processes. The problem with this is that if a process doesn't sent a heartbeat in 60 minutes, the backend will forget its dependencies, which was causing the list to only be the updated ones for some clients, specifically with gunicorn.

This makes forked processes also sent heartbeats with solved the issue in our tests.

Will stay as draft PR until I can check with @brettlangdon the reason heartbeats were disabled for forks.

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/dont-skip-fork-heartbeats-23040d3ddc072298.yaml      @DataDog/apm-python
ddtrace/internal/telemetry/writer.py                                    @DataDog/apm-core-python
tests/telemetry/test_telemetry.py                                       @DataDog/apm-python

[datadog-dd-trace-py-rkomorn]

Datadog Report

Branch report: juanjux/APPSEC-55999-SCA-forks-lose-dependencies
Commit report: 775ad5c
Test service: dd-trace-py

✅ 0 Failed, 1468 Passed, 0 Skipped, 23m 42.76s Total duration (12m 58s time saved)

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-12-03 10:30:04

Comparing candidate commit d144747 in PR branch juanjux/APPSEC-55999-SCA-forks-lose-dependencies with baseline commit 142e643 in branch main.

Found 2 performance improvements and 0 performance regressions! Performance is the same for 392 metrics, 2 unstable metrics.

scenario:iast_aspects-ospathbasename_aspect

• 🟩 execution_time [-455.931ns; -398.767ns] or [-12.217%; -10.685%]

scenario:iast_aspects-ospathdirname_aspect

• 🟩 execution_time [-397.708ns; -324.098ns] or [-9.868%; -8.041%]