Use address instead of host when determining the URL to use.

[aaron-coalesce]

Querying the hub for the emulator config by requesting127.0.0.1:4400/emulators gives the following:

{
  "hub": {
    "listen": [
      {
        "address": "0.0.0.0",
        "family": "IPv4",
        "port": 4400
      }
    ],
    "name": "hub",
    "host": "127.0.0.1",
    "port": 4400
  },
  "ui": {
    "listen": [
      {
        "address": "0.0.0.0",
        "family": "IPv4",
        "port": 4000
      }
    ],
    "name": "ui",
    "host": "127.0.0.1",
    "port": 4000,
    "pid": 66
  }
}

The listen.address is 0.0.0.0, so I would expect the UI logic to default to window.location.hostname but instead the links I see in the UI are 127.0.0.1. This appears to be because the code is looking at listen.host instead of listen.address. Changing references to listen.host to listen.address fixed the issue, and the UI links used the window's location instead of 127.0.0.1.

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[aaron-coalesce]

Looks like this got incorporated without me signing the agreement, so just closing the PR.