Fix “redefinition of module” errors for prebuilt XCFrameworks with module maps

Targets that depend on a prebuilt XCFramework shipping a module.modulemap no longer fail with “Redefinition of module ‘X’”. Xcode’s ProcessXCFramework already extracts the module map into $(BUILT_PRODUCTS_DIR)/include, so Tuist now skips adding the XCFramework slice’s Headers directory to HEADER_SEARCH_PATHS when a module map is present. This is a backport of the fix from #11472 for the 4.201.x line.