add pigeon native interop doc (#12982)

This pr adds a link to the pigeon native interop design doc.

Author: tarrinneal

firebase.json

@@ -629,6 +629,7 @@
       { "source": "/go/permissible-slider-interaction", "destination": "https://docs.google.com/document/d/151iaqbK-rZSRI34NdkvfIk4RkzOpAevoJ87TwiXfTpM/edit?usp=sharing&resourcekey=0-o0Gx6nrgl-fpw7_zUdMaQA", "type": 301 },
       { "source": "/go/per-pr-release", "destination": "https://docs.google.com/document/d/1wV2CuEKTxVgrVDghUrpipggqOt2D0TXARXGiZAFYUn8/edit?usp=sharing", "type": 301 },
       { "source": "/go/picture-lifecycle", "destination": "https://docs.google.com/document/d/1aTBj38k6NSVsYRwySEBItlqxdQbjzurjmHsXAr3yGiI/edit?usp=sharing&resourcekey=0-TbKDu4BVInqphkzAlasBnw", "type": 301 },
+      { "source": "/go/pigeon-native-interop", "destination": "https://docs.google.com/document/d/17qlMtoBdsjdPEv69u58TV4v2P-cJ5zPv7ZFMmIU4BZs/edit?usp=sharing", "type": 301 },
       { "source": "/go/platform-api-breakages", "destination": "https://docs.google.com/document/d/1OxDsf_eot7TlsRn57z-1_dGbvuqnMxO7QEGIAmOCZtA/edit?usp=sharing", "type": 301 },
       { "source": "/go/platform-based-key-events", "destination": "https://docs.google.com/document/d/1FDuxxEh810XpY561SgeiyUR0gU2eVz5kRpCFI55ibec/edit", "type": 301 },
       { "source": "/go/platform-channels-in-federated-plugins", "destination": "https://docs.google.com/document/d/1BSrDA_FjLU-3T0H774RocJ4IYyc0ytMl937rAimGJdg/edit?usp=sharing", "type": 301 },