Fix Lectern Controllers storing ItemStacks from nbt (Creators-of-Crea…

…te#7143)

Fixes Creators-of-Create#7143

src/main/java/com/simibubi/create/content/redstone/link/controller/LecternControllerBlockEntity.java

@@ -146,8 +146,8 @@ private void tryToggleActive() {
 	}
 
 	public void setController(ItemStack newController) {
-		controllerNbt = newController.getTag();
 		if (newController != null) {
+			controllerNbt = newController.getTag();
 			AllSoundEvents.CONTROLLER_PUT.playOnServer(level, worldPosition);
 		}
 	}