fix(runtime_metrics): avoid tracking multiple service names

[mabdinur]

Description

• Currently runtime metrics are tagged with every service name detected in a process. This is incorrect. Runtime metrics should only be tagged with global service names, global env, global version, global tracer tags, and platform tags.
• Also ensures runtime metric tracer tags are set everytime runtime metrics are flushed. This ensure runtime metrics are always sent with up to date values (and not just values set at start up or when service names are updated).

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/runtime-metrics-avoid-multiple-service-names-6895255636b5dfc7.yaml  @DataDog/apm-python
ddtrace/_trace/tracer.py                                                @DataDog/apm-sdk-api-python
ddtrace/internal/runtime/runtime_metrics.py                             @DataDog/apm-core-python
ddtrace/internal/runtime/tag_collectors.py                              @DataDog/apm-core-python
tests/tracer/runtime/test_runtime_metrics.py                            @DataDog/apm-sdk-api-python
tests/tracer/runtime/test_tag_collectors.py                             @DataDog/apm-sdk-api-python
tests/tracer/test_tracer.py                                             @DataDog/apm-sdk-api-python

[datadog-dd-trace-py-rkomorn]

Datadog Report

Branch report: munir/runtime-metrics-only-track-global-service-names
Commit report: 68ded36
Test service: dd-trace-py

✅ 0 Failed, 130 Passed, 1184 Skipped, 1m 50.7s Total Time

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 0% with 45 lines in your changes missing coverage. Please review.

Project coverage is 12.53%. Comparing base (8cdb084) to head (68ded36).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
tests/tracer/runtime/test_runtime_metrics.py	0.00%	27 Missing ⚠️
ddtrace/internal/runtime/runtime_metrics.py	0.00%	12 Missing ⚠️
ddtrace/internal/runtime/tag_collectors.py	0.00%	5 Missing ⚠️
tests/tracer/runtime/test_tag_collectors.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #12460      +/-   ##
==========================================
- Coverage   12.53%   12.53%   -0.01%     
==========================================
  Files        1389     1389              
  Lines      136465   136444      -21     
==========================================
- Hits        17106    17101       -5     
+ Misses     119359   119343      -16     

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[pr-commenter]

Benchmarks

Benchmark execution time: 2025-02-21 14:03:53

Comparing candidate commit 68ded36 in PR branch munir/runtime-metrics-only-track-global-service-names with baseline commit 7011d3c in branch main.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 418 metrics, 2 unstable metrics.