fix: stop RC tests on last expected request without requiring a trailing poll

[smola]

Motivation

The validate() functions in RC sequence tests used to return True only when called with a request AFTER all expected ones had been validated, requiring an extra trailing RC poll. This made them fragile when the tracer stops polling shortly after the last mocked response.

This can happen in tracers that support the /flush mechanism and so the setup phase exits before an additional RC poll request happening. Related to #6772

Changes

Fix: return True directly after validating and incrementing on the last expected request, removing the need for any additional poll.

Workflow

1. ⚠️ Create your PR as draft ⚠️
2. Work on you PR until the CI passes
3. Mark it as ready for review
   • Test logic is modified? -> Get a review from RFC owner.
   • Framework is modified, or non obvious usage of it -> get a review from R&P team

🚀 Once your PR is reviewed and the CI green, you can merge it!

🛟 #apm-shared-testing 🛟

Reviewer checklist

• Anything but tests/ or manifests/ is modified ? I have the approval from R&P team
• A docker base image is modified?
  • the relevant build-XXX-image label is present
• A scenario is added, removed or renamed?
  • Get a review from R&P team

[github-actions]

CODEOWNERS have been resolved as:

tests/remote_config/test_remote_configuration.py                        @DataDog/remote-config @DataDog/system-tests-core

[datadog-official]

🎉 All green!

❄️ No new flaky tests detected
🧪 All tests passed

_{This comment will be updated automatically if new data arrives.
🔗 Commit SHA: 84c0836 | Docs | Datadog PR Page | Give us feedback!}