I don't think there are any restrictions on bringing in canned foie gras. Aphis uses the description "thoroughly cooked" which it would seem that foie gras is.

Here's the Aphis rule:

"If the product is cooked, perishable poultry the product is enterable in
passenger baggage if, upon visual inspection, CBP officials confirm the
poultry meat and poultry meat products appear “thoroughly cooked”
throughout."