Fix integration of swift-testing

[fortmarek]

Resolves #5795

Short description 📝

This PR fixes the integration of swift-testing. There were two issues:

• in the hardcoded mapping for test targets, we were missing the Testing framework. Long-term, we should still find an automatic way to derive whether we should add the ENABLE_TESTING_SEARCH_PATHS or not.
• allSwiftMacroTargets method in the GraphTraverser wouldn't actually return a direct macro dependency.
• The copy macro build phase must be before the compile sources phase for targets that directly depend on a macro

How to test the changes locally 🧐

You should be able to test AppKit in the app_with_spm_dependencies fixture.

Contributor checklist ✅

• The code has been linted using run mise run lint:fix
• The change is tested via unit testing or acceptance testing, or both
• The title of the PR is formulated in a way that is usable as a changelog entry
• In case the PR introduces changes that affect users, the documentation has been updated

Reviewer checklist ✅

• The code architecture and patterns are consistent with the rest of the codebase
• Reviewer has checked that, if needed, the PR includes the label changelog:added, changelog:fixed, or changelog:changed, and the title is usable as a changelog entry