Missing readonly `inboundIpAddress` property from Microsoft.Web/sites type definitions

If I perform a GET on a resource of type Microsoft.Web/sites with API version 2018-11-01, the response includes a property named `inboundIpAddress` under the resource "properties" field:

```json
{
"id": // removed,
"name": // removed,
"type": "Microsoft.Web/sites",
"kind": "app",
"location": "Central US",
"properties": {
// removed,
"inboundIpAddress": // removed,
// removed,
}
}
```

This property has not been declared anywhere in any of the Microsoft.Web specs. I assume there are other similar properties which have not been modeled, and that this issue is present in many of the different API versions supported by the service.

This was first brought to our attention here: https://github.com/Azure/bicep/issues/784#issuecomment-776486990

Start by locating the Microsoft.Web specifications for API version 2018-11-01 and compare the reported Microsoft.Web/sites response with the declared properties. Determine which specification files and supported API versions need the readonly inboundIpAddress property, then verify that the affected type definitions represent the response consistently.

Written by the indexing model from the issue text.