Restricts Inventory Picker If Previously Sent Non-Active Offer

[Step7750]

For example:

• User creates offer for commodity item X called A
• User also uses another marketplace such that it sends asset X to a different user
• Trade offer A is now invalidated

Previously, the extension wouldn't restrict the inventory picker, so the user could ignore the warnings and override the system more easily. We now will block the picker if there is also no "active" offer to the buyer for that item.