Change suggestion containing a new table with header column and cell split is not applied correctly when using getDataWithAcceptedSuggestions()

[lkszzajac]

📝 Provide detailed reproduction steps (if any)

1. Open an editor with Table, TrackChanges and TrackChangesData plugins (e.g. ckeditor5/external/ckeditor5-commercial/packages/ckeditor5-collaboration/tests/manual/all-features-rtc.html)
2. Enable Track Changes and perform these actions:
   1. Add a 5x5 table.
   2. Add a header column
   3. Split one of the cells in the header column
3. Extract data from the document using editor.plugins.get("TrackChangesData").getDataWithAcceptedSuggestions()

✔️ Expected result

• extracted table markup has the same structure as in editor

❌ Actual result

• extracted table includes 4 additional columns at the end
• header row is applied

📃 Other details

• Browser: n/a
• OS: n/a
• First affected CKEditor version:
• Installed CKEditor plugins:

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[mmotyczynska]

The bug can be reproduced without using Track Changes.

1. Open the documentation for tables: https://ckeditor.com/docs/ckeditor5/latest/features/tables/tables.html
2. Insert a 5x5 table.
3. Convert the first column to a header column.
4. Horizontally split one of the cells in the header column.
5. Set the current data using the Inspector or in the console: editor.setData( editor.getData() )

This results in the table expanding to an unintended size (9x6). Additionally, it then becomes impossible to undo any changes.
https://github.com/user-attachments/assets/4fab1855-5fbb-409f-8807-8cbacdc47cfb

[Mati365]

I checked this, works fine after fix merged in #17640.