Fix cached nested static-ObjC xcframework consumption (ARCore)

Tuist now distinguishes nested (module map and headers inside a Headers/<ModuleName>/ subdirectory, like Google’s ARCore xcframeworks) from flat static Objective-C xcframeworks when consuming them through the binary cache. Nested ones are consumed through their own module map with the xcframework Headers root on the search path, so the module is defined exactly once and header cross-imports like <ModuleName/Sibling.h> resolve. The earlier rc.3 fix that added the Headers root next to a derived module map caused import of shadowed module errors for ARCore-shaped xcframeworks; this corrects it.