feat: remove iron bars

Minecraft.World/Zombie.cpp

@@ -347,7 +347,7 @@ int Zombie::getConversionProgress()
 				{
 					int tile = level->getTile(xx, yy, zz);
 
-					if (tile == Tile::ironFence_Id || tile == Tile::bed_Id)
+					if (tile == Tile::bed_Id)
 					{
 						if (random->nextFloat() < 0.3f) amount++;
 						specialBlocksCount++;