logout-menu: fixed widget button bg color, fixed rows fg color

[Luka5W]

1. foreground colors of rows were not updated in light theme
   • expected behavior: text is readable
   • current behavior: text is always white (even with light themes)
2. background color of widget button stays active/ focused after clicking on one rows. not disturbing when logging out, shutting down or rebooting but when locking or suspending.
   • expected behavior: button background color is reset when an action is executed (a row is clicked on).
   • current behavior: button keeps active until the menu is opened and closed again (button background changes only when clicked on it).

this pr does not change any icon colors (they're still light/ grey). i'm not sure how to change them: either by

• duplicating the files, change the color in the svg (hard coded like it is now)
• keep the files, change the color with lua