config_consistency: Enable tests for the python and ruby tracers

[mabdinur]

Motivation

• Enables all python and ruby config consistency tests that are XPassing.

Changes to server.rb

• Updates the start_span endpoint in the ruby parametric app to avoid setting service, resource, and type arguments to an empty string by default. The default values for these arguments MUST be nil.
• Ensures the find_span helper in the ruby parametric app can retrieve spans that are not active. There is not need to only allow parametric endpoints to operate on active spans. This change allows us to test scenarios when the tracing api is used AND DD_TRACE_ENABLED=False.

Minor changes (not required)

• Refactors tests in tests/parametric/test_config_consistency.py to improve readability

Workflow

1. ⚠️ Create your PR as draft ⚠️
2. Work on you PR until the CI passes (if something not related to your task is failing, you can ignore it)
3. Mark it as ready for review
   • Test logic is modified? -> Get a review from RFC owner. We're working on refining the codeowners file quickly.
   • Framework is modified, or non obvious usage of it -> get a review from R&P team

🚀 Once your PR is reviewed, you can merge it!

🛟 #apm-shared-testing 🛟

Reviewer checklist

• If PR title starts with [<language>], double-check that only <language> is impacted by the change
• No system-tests internal is modified. Otherwise, I have the approval from R&P team
• CI is green, or failing jobs are not related to this change (and you are 100% sure about this statement)
• A docker base image is modified?
  • the relevant build-XXX-image label is present
• A scenario is added (or removed)?
  • Get a review from R&P team