Allow barters to interact with produce sacks

[Dawidio123]

When i first saw produce sacks i was kinda meh about it but then i thought oh shit it might be a stockpile that can be left at 0 items and still exist in the world, perfect for some basic barter stand usage because buying it out doesn't remove the stockpile from existence. But nope, that doesn't work.
Just allow produce sacks to be interacted with same way stockpiles are using barters.