fix(history): don't save both action prefix and displayed name

Displayed name is already added to action messages when added to ChatForm. Saving in history as well results in the display name being displayed twice when loaded from history.

src/widget/widget.cpp

@@ -1212,7 +1212,7 @@ void Widget::onFriendMessageReceived(int friendId, const QString& message, bool
         QString name = f->getDisplayedName();
         QString text = message;
         if (isAction) {
-            text = ChatForm::ACTION_PREFIX + f->getDisplayedName() + " " + text;
+            text = ChatForm::ACTION_PREFIX + text;
         }
         profile->getHistory()->addNewMessage(publicKey, text, publicKey, timestamp, true, name);
     }