Napi will render disallowed content of `<clipPath>`

[noahbald]

The clipPath element should not render content that is not part of it's content-model.

For example, the following SVG will incorrectly use <g><rect ... /></g> despite it not being in it's content model.

<?xml version="1.0"?>
<svg xmlns="http://www.w3.org/2000/svg" width="128" height="128">
  <defs>
    <clipPath id="a">
      <g>
        <rect width="64" height="128"/>
      </g>
    </clipPath>
  </defs>
  <g clip-path="url(#a)">
    <rect width="128" height="64"/>
  </g>
</svg>

This image will render a red square.

However, the image should be blank.