Update ChestShopSign to persist sign data

The ChestShopSign class has been updated to correctly persist sign data. An update method call has been added after setting persistent data, to ensure changes are saved and persisted within the server.

src/main/java/com/Acrobot/ChestShop/Signs/ChestShopSign.java

@@ -159,6 +159,7 @@ public static void saveChestShopMetaData(Sign sign, ChestShopMetaData chestShopM
 
             String string = yamlConfiguration.saveToString();
             sign.getPersistentDataContainer().set(METADATA_NAMESPACED_KEY, PersistentDataType.STRING, string);
+            sign.update();
 
         } catch (Exception e) {
             Bukkit.getLogger().log(Level.WARNING,