Unity opensource: Fixed build issue with nanopb on kokoro windows
Unity opensource: Fixed build issue with nanopb on kokoro windows

PiperOrigin-RevId: 271606877

firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk,firebase/firebase-cpp-sdk