What is the ruling on borrowing with usury by purchasing a commodity, then dividing the borrowed amount with a friend, and sharing the repayment of the principal and the accrued interest?

This transaction is a financing one (murabaha sale or installment sale), not a loan, because a loan with interest is forbidden usury. As for murabaha, it is a permissible sale. If the bank owned the rice before selling it to both of you, then there is no harm in selling it for a known price, even if it is more than its value. What you did by purchasing the commodity for yourself and your friend is considered agency, and therefore, the price of the commodity is between the two of you, and each of you should pay half of the debt.