iframe being rendered strangely in the canvas view

使用自定义代码块复现官方演示中的 iframe 行为，然后将 canvas 视图与 View code 模态框和 editor.getHtml() 进行比较。追踪 canvas 将 iframe 替换为 div 并移动其属性的位置；完成标准是 canvas 保留 iframe 布局，并且仍与模型输出保持一致。

Hello,

The issue described below can be reproduced on the official demo at https://grapesjs.com/demo.html

When I try to add an iframe in a custom code block, the view tends to replace the iframe by a div, which breaks the layout of the iframe. However, the model seems to have the correct iframe since it is shown correctly in the view code modal, or by using editor.getHtml().

For example, if I add this iframe which is an embed YouTube video:

<iframe width="560" height="315" src="https://www.youtube-nocookie.com/embed/dQw4w9WgXcQ?si=m6l8dvLYog_PS9a4" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>

This is what the canvas view will use, parts of the iframe attributes are now on a parent div:

<div data-gjs-highlightable="true" id="i73h" data-gjs-type="custom-code" draggable="true">
  <div id="i5xd" data-gjs-type="video" draggable="true" allowfullscreen="" width="560" height="315" src="https://www.youtube-nocookie.com/embed/dQw4w9WgXcQ?si=m6l8dvLYog_PS9a4" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" class="gjs-hovered">
    <iframe src="https://www.youtube-nocookie.com/embed/dQw4w9WgXcQ?" frameborder="0" allowfullscreen="true" class="gjs-no-pointer" style="height: 100%; width: 100%;"></iframe>
  </div>
</div>