RUM-5650 chore: Refine Smoke Tests and add Swift 5.9 coverage

[ncreated]

What and why?

📦 This PR reorganizes and improves the coverage of smoke tests for our iOS SDK. It now includes coverage for all supported Swift versions while maintaining compatibility with various dependency managers.

How?

The smoke-test stage has been streamlined to 4 key jobs:

• Smoke Test (iOS) and Smoke Test (tvOS): These jobs test SDK integration through CocoaPods, Carthage, Xcode's SPM, and XCFrameworks. They run on a macos:sonoma runner with Xcode 15.4.

• SPM Build (Swift 5.9): This job builds Package.swift for each supported platform using the macos:ventura runner with Xcode 15.2.

• SPM Build (Swift 5.10): Similar to the above, but for Swift 5.10 using the macos:sonoma runner with Xcode 15.4.

The two "SPM Build" jobs now fully mirror SDK builds in Swift Package Index.

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

[datadog-datadog-prod-us1[bot]]

Datadog Report

Branch report: ncreated/RUM-5650/enhance-smoke-testing-on-ci Commit report: d06a030 Test service: dd-sdk-ios

:white_check_mark: 0 Failed, 3470 Passed, 0 Skipped, 2m 19.59s Total Time :snowflake: 1 New Flaky :small_red_triangle_down: Test Sessions change in coverage: 3 decreased, 6 increased, 5 no change

New Flaky Tests (1)

• testWhenEnabled_itSendsConfigurationTelemetry - SessionReplayTests - Last Failure

  Expand for error

  ``` Assertion Failure at SessionReplayTests.swift:198: XCTUnwrap failed: expected non-nil value of type "ConfigurationTelemetry" ```

:small_red_triangle_down: Code Coverage Decreases vs Default Branch (3)

• test DatadogTraceTests tvOS 54.22% (-0.11%) - Details
• test DatadogRUMTests tvOS 81.19% (-0.03%) - Details
• test DatadogRUMTests iOS 81.09% (-0.01%) - Details