Extra line added when deleting unsubscribe text

[noepena]

Go to mosaico demo, click to edit unsubscribe text, delete all text. An extra space is added under the text. Then when you type new text the extra space remains and cannot be deleted.
In all other data-ko-editable fields the extra space is added when all text is deleted then we you type in new text the space is removed automatically.

Expected behavior: extra space is removed automatically.
Actual behavior: extra space remains and cannot be removed by the user.