Add focus to kebab menu options for comment when using keyboard

related to WCAG level AA criteria 2.4.7: focus visible
https://www.w3.org/TR/WCAG21/#focus-visible

Location of the element: "Comments" tab section, under the "Tags" heading, in the main content.

Steps to reproduce
1. Enter any comment in the "Write a comment here" edit field.
2. Then click on the "Save" button. Then the comment will add in the comments tab section.

USING THE KEYBOARD ONLY FROM NOW ON
3. Access the "More options" button using the tab key (note that button does not appear due to WEBUI-556).
4. Press enter
5. Try to select the edit or delete options using the arrow keys

=> No focus is put on these options
Expected: when using these buttons with the keyboard, they should receive focus so that a user can tell which element they are interacting with