Forms: Columns block in the form editor don't work as expected

### Impacted plugin

Jetpack

### Quick summary

Currently when you add the columns block inside the form block. You end up with a situation where the a single column takes up 100% of the width of the forms block. Which means that a 2 columns blocks takes somehow take up 200% of the width of the editor.

See


Notice the scroll bar at the bottom.

Notice that this feature only impacts the block editor.

### Steps to reproduce

1. Add the forms block. Pick a form.
2. Add the columns block inside the forms block.
3. Notice that the columns block take up a lot more space then expected.
4. The expectation is that he columns block would work the same if it was placed inside the form or not.

### Site owner impact

Fewer than 20% of the total website/platform users

### Severity

Moderate

### What other impact(s) does this issue have?

_No response_

### If a workaround is available, please outline it here.

_No response_

### Platform (Simple and/or Atomic)

Simple, Atomic, Self-hosted

Start by reproducing the issue in the WordPress block editor with a forms block containing a columns block, then inspect the form and columns block entry points. Done means columns inside the form use the same width behavior as columns placed outside it, without horizontal overflow.

Written by the indexing model from the issue text.