make roomList more data safe

online_status_list/src/RoomOnlineListPanel.svelte

@@ -16,11 +16,13 @@ interface Room {
 
 export let title: string;
 export let rooms: Room[];
+
+$: safeRoomList = Array.isArray(rooms) ? rooms : [];
 </script>
 
 <nav class="panel is-primary">
   <p class="panel-heading">{title}</p>
-  {#each rooms as room (room.url)}
+  {#each safeRoomList as room (room.url)}
     <SingleRoomPanelBlock {...room} />
   {/each}
 </nav>