Multiple line breaks and bringing the cursor back causes an error.

Describe a bug.
```
TypeError: undefined is not an object (evaluating 'l.children.length')
```

Steps to reproduce:
1. write paragph
2. shift+enter for multiple line breaks
3. Returns the cursor to the start of a new line.
4. Press the right button to advance the cursor.
5. and back
6.

Expected behavior:

Screenshots:

https://github.com/codex-team/editor.js/assets/2194021/f17c24c4-bb3b-4e76-b6c3-dfd1596972da

Device, Browser, OS:
- mac m1 13.0
- safari 16.1

Editor.js version:
"@editorjs/editorjs": "^2.27.0",