A contextually aware UNO command of the current Text Attributes command (.uno:TextAttributes) is needed for usage in the context menu. It should be enabled when a shape or textbox has text in it and disabled otherwise.
@Gulsah: If you get some free time. Thanks for all the work you've been doing with all of these new UNO commands. :D
@Yousuf: I added it to my bug list :)