Emulator not handling 0.0.0.0 hostname definition in firebase.json

[StorminGorman]

[REQUIRED] Environment info

firebase-tools: 8.13.1

Platform: MacOS Catalina

[REQUIRED] Test case

Try to make the emulators host on external network interfaces on the local network.

[REQUIRED] Steps to reproduce

Add the following to the firebase.json to host on external network interfaces

  "emulators": {
    "functions": {
      "port": 5001,
      "host": "0.0.0.0"
    },
    "firestore": {
      "port": 9090
    },
    "database": {
      "port": 9000,
      "host": "0.0.0.0"
    },
    "hosting": {
      "port": 5000,
      "host": "0.0.0.0"
    }
  }

Then run firebase --debug emulators:start

Emulators fail to start

[REQUIRED] Expected behavior

Should be able to host emulators on external network interfaces.

[REQUIRED] Actual behavior

emulators fail to start.
WARN com.firebase.core.namespace.NamespaceActorSystem - Request for ns: checkit-portico has incorrect domain. Current domain: 0.0.0.0, expected domain: firebaseio-staging.com\n"}}

firebase-debug.log

[samtstern]

@StorminGorman thanks for the report! This looks like a duplicate of #2633 so let's discuss over there.