fix: don't display date on ("new") message divider

src/pages/channels/messaging/MessageRenderer.tsx

@@ -126,7 +126,7 @@ export default observer(({ last_id, renderer, highlight }: Props) => {
         if (unread || date) {
             render.push(
                 <MessageDivider
-                    date={dayjs(date).format("LL")}
+                    date={date ? dayjs(date).format("LL") : undefined}
                     unread={unread}
                 />,
             );