Select all columns in previous table rows when the last row is fully selected.

[Mati365]

Suggested merge commit message (convention)

Fix (table): Improve selection of the cells with colspan attribute. Closes #17538

MINOR BREAKING CHANGE (table): The TableSelection#getSelectedTableCells method now considers cells with a colspan. If the selection ends on a cell with a colspan, it will be adjusted to the end of that cell, and all cells above it will be returned, instead of just one.

MINOR BREAKING CHANGE (table): The TableSelection#setCellSelection method has been updated to behave consistently with the updated getSelectedTableCells, ensuring that cell selection is aligned with the new behavior regarding cells with a colspan.

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Additional information

I normalized cell-span selection behaviour to make it work in similar way it works in TinyMCE.

Before

before-fix-selection-v3-2024-12-30_13.21.34.mp4

before-selection-fix-2024-12-30_10.40.55.mp4

After

after-fix-selection-v3-2024-12-30_13.19.51.mp4

after-fix-selection-2024-12-30_13.17.30.mp4

[Mati365]

GDocs behaviour:

gdocs-2024-12-30_12.03.54.mp4

[charlttsie]

I've done some testing, and the fix looks good to me. The issue no longer reproduces, and I haven't found any regressions 👍

[arkflpc]

I have one doubt about the suggested merge commit message. You mentioned getSelectedTableCells but it seems not be affected by the changes (setCellSelection is). You also didn't mention what class this method belongs to.