Fix Xcode 26 “expected exactly one compiler job” build failures

Projects with many precompiled framework search paths, commonly from Tuist binary caching, could fail to build on Xcode 26 with errors about exactly one compiler job or clang importer creation. Tuist now passes the framework-search-path response file to OTHER_SWIFT_FLAGS as a bare @resp token instead of -Xcc @resp, letting swift-driver expand the flags correctly and keeping the build moving.