Split text functionality for CKEditor 5 only supports "paragraph" widget

Problem/Motivation

The work from ✨ Split text functionality for CKEditor 5 Fixed works specifically with the "paragraph" widget and not other entity_reference_revisions widgets that support paragraphs (e.g., "layout_paragraphs").

Steps to reproduce

- Install and enable Layout Paragraphs → and Paragraphs Features → modules.
- Configure a text format to use CKEditor 5 and the Split Text button.
- Configure a paragraph type that includes a "Formatted text" field, using the text format configured previously.
- Create a paragraphs field that can reference the previously configured paragraph type and use the "layout_paragraphs" widget on the form display.
- Note when editing, the opened layout paragraphs dialog that presents the editor shows the split text button but it is disabled.

Proposed resolution

Explore and integrate support for the "layout_paragraphs" widget.