fix: Previews crash when accessing resources from cached XCFrameworks

[anlaital-oura]

This is continuation of #6008.

Short description 📝

SPM has the #if DEBUG guard within which ProcessInfo is used. It works because SPM doesn't precompile anything, so compiling the bundle accessor happens with debug configuration.

However, if you run tuist cache for all dependencies and then tuist generate SomeFramework, it will cause a crash when running Previews as tuist cache builds for release mode and resulting code will bypass this check. It still works with the previous implementation if running tuist generate SomeFramework DependencyWithResources, but that defeats the point of caching and makes using Previews less predictable.

While I wanted to stay as close to the original SPM implementation as possible, I don't think there is any harm in checking for this environment variable in release configuration either. It will simply be not set.

How to test the changes locally 🧐

1. cd fixtures/app_with_previews
2. tuist install
3. tuist cache
4. tuist generate PreviewsFramework
5. Open TestView.swift and tap on the button in Previews and it will crash

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

[fortmarek]

As you mention, removing the DEBUG compiler directive should be fine as the PACKAGE_RESOURCE_BUNDLE_PATH variable should be simply not defined outside of previews