fix(cli): show scheme test configuration in build runs

What changed

• Use the scheme test-action configuration when uploading tuist test build runs and no explicit CLI --configuration was provided.
• Keep the explicit CLI configuration as the highest-priority value when it is present.
• Update the focused TestService test to assert that the uploaded build-run metadata receives the scheme configuration.

Why

tuist test can run with a concrete configuration from the selected scheme even when the user does not pass --configuration. The build-run upload path only forwarded the CLI argument, so those runs were uploaded with a nil configuration and the Build Runs UI displayed Unknown.

Root cause

The test service already had access to the resolved scheme, including scheme.testAction?.configurationName, but uploadBuildRunIfNeeded was called with only the optional CLI configuration argument. When that argument was absent, the metadata upload lost the scheme configuration.

Approach

The upload call now falls back from the CLI configuration to scheme.testAction?.configurationName. This keeps command-line overrides intact while preserving the scheme default for build-run metadata.

Impact

Build Runs created by tuist test should show the scheme test configuration more consistently instead of Unknown when the configuration comes from the scheme.

Validation

• Ran git diff --check.
• Ran xcsiftbuild test -workspace Tuist.xcworkspace -scheme Tuist-Workspace -only-testing TuistKitTests/TestServiceTests/test_run_uploads_build_run_using_passthrough_derived_data_path CODE_SIGNING_ALLOWED=NO CODE_SIGNING_REQUIRED=NO CODE_SIGN_IDENTITY="" COMPILATION_CACHE_ENABLE_CACHING=NO — 1 passed, 0 failed.