bug: redo doesn't restore image

[dominikagoral]

Steps to reproduce:

1. Add an image into a column.
2. Set the image to a custom one.
3. Click "undo".
4. Click "redo".

Result: the image doesn't come back.
Expected result: the image is restored.

⚠ Only a case with columns, works fine in tables.

[dominikagoral]

This is a bug in the mj-image component that also occurs in the official demo.
It should be possible to extend the component to prevent this issue from happening.

[dominikagoral]

Reported the issue to the parent repo here: GrapesJS/mjml#389.