Don't parse implicit properties with nested property microformats

[nex3]

Checklist

• [x] Added tests covering the parsing behaviour changes.

Changes to parsing behaviour

Previously, this was checking the same array returned by findChildren(). However, findChildren() excludes children that are the values of properties themselves. Per spec, if there are any nested microformats implicit properties should not be parsed.

This now matches the behavior of https://php.microformats.io/.

Example input covered by new behaviour

<div class="h-entry">
  <a href="http://example.com/"></a>
  <div class="p-author h-card">
    <span class="p-name">microformats</span>
  </div>
</div>

Example output from new behaviour

{
  "properties": {
    "author": [
      {
        "properties": {
          "name": ["microformats"]
        },
        "type": ["h-card"],
        "value": "microformats"
      }
    ]
  },
  "type": ["h-entry"]
}