chore(ci_visibility): flesh out support for ITR in manual API

[romainkomorndatadog]

Adds support to the manual API for ITR-related activity:

• counting skippable/skipped items
• unskippable and forced run tags
• adds ITR-related settings to CIVisibilitySessionSettings
• only settings ITR-related tags when ITR is enabled
• ensuring that skipped counts only counts suites when in suite-skipping mode (CIVIS-8754)

CIITRMixin is introduced for the external API, since both suites and tests support ITR.

Some other minor changes include:

• use class name instead of base class names (shorter and nicer)
• shuffling some args namedtuple definitions around for cosmetic reasons
• test updates to properly simulate suite-level skipping

Checklist

• Change(s) are motivated and described in the PR description
• Testing strategy is described if automated tests are not included in the PR
• Risks are described (performance impact, potential for breakage, maintainability)
• Change is maintainable (easy to change, telemetry, documentation)
• Library release note guidelines are followed or label changelog/no-changelog is set
• Documentation is included (in-code, generated user docs, public corp docs)
• Backport labels are set (if applicable)
• If this PR changes the public interface, I've notified @DataDog/apm-tees.
• If change 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.

Reviewer Checklist

• Title is accurate
• All changes are related to the pull request's stated goal
• Description motivates each change
• Avoids breaking API changes
• Testing strategy adequately addresses listed risks
• Change is maintainable (easy to change, telemetry, documentation)
• Release note makes sense to a user of the library
• 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

[datadog-dd-trace-py-rkomorn]

Datadog Report

Branch report: romain.komorn/CIVIS-2943/itr_fetching_tests
Commit report: 7cb2730
Test service: dd-trace-py

✅ 0 Failed, 36249 Passed, 18 Skipped, 11m 21.13s Wall Time

[pr-commenter]

Benchmarks

Benchmark execution time: 2024-03-29 08:44:02

Comparing candidate commit 868f280 in PR branch romain.komorn/CIVIS-2943/itr_fetching_tests with baseline commit 8ab2d72 in branch main.

Found 4 performance improvements and 0 performance regressions! Performance is the same for 197 metrics, 9 unstable metrics.

scenario:httppropagationextract-large_header_no_matches

• 🟩 max_rss_usage [-746.562KB; -484.286KB] or [-3.411%; -2.213%]

scenario:httppropagationextract-none_propagation_style

• 🟩 max_rss_usage [-1027.047KB; -762.905KB] or [-4.695%; -3.487%]

scenario:httppropagationextract-wsgi_large_header_no_matches

• 🟩 max_rss_usage [-750.469KB; -676.987KB] or [-3.432%; -3.096%]

scenario:httppropagationextract-wsgi_medium_header_no_matches

• 🟩 max_rss_usage [-764.930KB; -689.559KB] or [-3.499%; -3.154%]

[erikayasuda]

A couple of non-blocking questions for my own understanding. Otherwise LGTM!