fix(oas3): validate xml and x-www-form-urlencoded request body

[glowcloud]

Refs #9673

[glowcloud]

We might need to get rid of nodes with only whitespace characters here, as at this point our result is this:

{
    "0": "\n",
    "1": "\t",
    "id": "10",
    "name": "doggie",
    "category": {
        "0": "\n",
        "1": "\t",
        "2": "\t",
        "id": "1",
        "name": "Dogs"
    }
}

The validation for this will pass but perhaps it might create issues later on.

[glowcloud]

This is fine if the type of our parameter is an object but if we have an array, ex.

	<photoUrls>
		<photoUrl>a</photoUrl>
		<photoUrl>b</photoUrl>
		<photoUrl>c</photoUrl>
	</photoUrls>

the JSON result for it will be

{
  "photoUrls": {
      "photoUrl": "c"
  }
}

and that's the only thing we'll be validating.

Perhaps we could do something like this

  let isArray = false
  Object.entries(child).forEach(([key, value]) => {
    if (paramObj[key] === undefined) {
      paramObj[key] = value
    } else if (isArray) {
      paramObj[key].push(value)
    } else {
      paramObj[key] = [paramObj[key], value]
      isArray = true
    }
  })
  if (isArray) {
    paramObj = Object.values(paramObj)[0]
  }

In this case, arrays of length 0 or 1 would still be seen as an object.

[glowcloud]

As I mentioned in a comment

We might need to get rid of nodes with only whitespace characters

Perhaps we could just add if (typeof child !== "string") here, as traversedChildren will look something like this:

[
    "\n\t\t",
    {
        "id": "1"
    },
    "\n\t\t",
    {
        "name": "Dogs"
    },
    "\n\t"
]

It seems like the actual parameters should be { key: value } objects.

[glowcloud]

Not sure about the name of this function, perhaps it should be xmlToJson to better reflect what it does.