you did a wrong thing here. You had asked a question (“Use LibreOffice dialogs” configuration location), and got an answer. Okay, but then you suddenly provided your own answer, and changed the question’s title “Update “Use LibreOffice dialogues” user preference with script”, so now my answer is no more relevant to what is asked here.
Please don’t do such things. You needed to let this question be as it was, and create another question about scripted update, and add your answer there. Then it would be logical and not confusing.