Remove obsolete shim items for Bed and Skull

now that the colour and skull type are included in the block type data, it's no longer necessary to maintain shim items to retain this information in the item data.

src/data/bedrock/item/ItemDeserializer.php

@@ -536,7 +536,7 @@ final class ItemDeserializer{
 			}catch(\InvalidArgumentException $e){
 				throw new ItemTypeDeserializeException($e->getMessage(), 0, $e);
 			}
-			return Items::MOB_HEAD()->setSkullType($skullType);
+			return Blocks::MOB_HEAD()->setSkullType($skullType)->asItem();
 		});
 		//TODO: minecraft:skull_banner_pattern
 		$this->map(Ids::SLIME_BALL, fn() => Items::SLIMEBALL());