Fix for fix #36345, TinyMCE, make sure iframe is fully loaded

[Fedik]

Pull Request for Issue #36345 for fix #24343

Summary of Changes

Make sure the script listen iframe load event only once.

Testing Instructions

Apply patch, run npm install

Create subform with editor (example in Custom HTML):

<field type="subform" name="subform" multiple="true" label="subform">
  <form>
    <field type="editor" name="text" label="editor" buttons="false"  default="I am a text!"/>
  </form>
</field>

Run test in Chrome and Firefox, and Safari (if you have one).

Make sure the Article content editor works correctly.

Then add couple rows in subform and try sort them. Then watch editor content.

Actual result BEFORE applying this Pull Request

In Firefox the Article content editor realods itself, and not able to edit content.

Expected result AFTER applying this Pull Request

In all Browsers the content editor works correctly.
Content in subform editor works after sorting.

Link to documentations

Please select:

• No documentation changes for docs.joomla.org needed
• No documentation changes for manual.joomla.org needed

[Fedik]

@Quy please test

[Quy]

I have tested this item ✅ successfully on d4de355

Thank you!

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[richard67]

I have tested this item ✅ successfully on d4de355

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[richard67]

RTC

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[fancyFranci]

Thank you for fixing the fix :)