chore: Disable flaky OTelSpan.testSetActive_givenParentSpan() test

[ncreated]

What and why?

📦 ❄️ This PR disables flaky OTel test (testSetActive_givenParentSpan()). This is to address recent CI failures.

How?

Disabled failed test and created RUM-4795 to re-enable it when possible.

I also revamped the whole OTelSpanTests suite to take dependency on FeatureScope rather than core mock. This is to address mid-term goals from #1744 - having less and simpler dependency in tests so they run faster, more stable and are easier to debug.

Review checklist

• Feature or bugfix MUST have appropriate tests (unit, integration)
• Make sure each commit and the PR mention the Issue number or JIRA reference
• Add CHANGELOG entry for user facing changes

Custom CI job configuration (optional)

• Run unit tests for Core, RUM, Trace, Logs, CR and WVT
• Run unit tests for Session Replay
• Run integration tests
• Run smoke tests
• Run tests for tools/

[datadog-datadog-prod-us1]

Datadog Report

Branch report: ncreated/chore/disable-flaky-OTel-tests
Commit report: 1d047f5
Test service: dd-sdk-ios

✅ 0 Failed, 3235 Passed, 0 Skipped, 2m 25.84s Total Time
🔻 Test Sessions change in coverage: 9 decreased, 3 increased, 1 no change

🔻 Code Coverage Decreases vs Default Branch (9)

This report shows up to 5 code coverage decreases.

• test DatadogTraceTests iOS 54.69% (-0.6%) - Details
• test DatadogTraceTests tvOS 55.22% (-0.3%) - Details
• test DatadogRUMTests iOS 81.25% (-0.21%) - Details
• test DatadogCrashReportingTests tvOS 27.32% (-0.07%) - Details
• test DatadogCrashReportingTests iOS 27.29% (-0.07%) - Details

[maxep]

👍

[ganeshnj]

should we do for tvOS too?