BUG: A border on the mj-column is shown twice in the editor

GrapesJS version

• I confirm to use the latest version of GrapesJS

What browser are you using?

Chrome 102.0.5005.61

Reproducible demo link

https://codepen.io/adiux/pen/BaYrEXR?editors=1111

Describe the bug

How to reproduce the bug?

1. Add grapesjs-mjml to the project with any version newer than 0.5.6
2. Add a border to a section. E.g.: <mj-column border="4px solid #F45E43">
3. Open MJML template with grapesjs

What is the expected behavior? only one border is shown: <img width="792" alt="image" src="https://user-images.githubusercontent.com/13075514/171250244-f96c395b-5a6e-4cde-a7f4-f60d778c9a15.png">

What is the current behavior? two borders are shown: <img width="766" alt="image" src="https://user-images.githubusercontent.com/13075514/171249926-6ed65f00-c09e-4c0c-a668-94fcc59fca0d.png">

If is necessary to execute some code in order to reproduce the bug, paste it here below:

// Working
import grapesjsMjml from "https://cdn.skypack.dev/[email protected]";

// Not working
import grapesjsMjml from "https://cdn.skypack.dev/[email protected]";
import grapesjsMjml from "https://cdn.skypack.dev/[email protected]";

Note: The rendered HTML is fine. It is only an issue with the editor.

Code of Conduct

• I agree to follow this project's Code of Conduct