BUG: CKEditor table button icons missing

[markusguenther]

Description

The buttons of the CKEditor table actually don't show the icon. The fallback labels take a lot of space and are not well aligned.
This happens since Neos UI version 8.3.10.

Steps to Reproduce

1. Create a text node
2. Add a table
3. Check the row and col buttons

Expected behavior

The buttons have just an icon and don't render the fallback label.

Actual behavior

The fallback labels are rendered.

Affected Versions

Neos: 8.3

UI: 8.3.10