Nothing in this Act shall be construed as invalidating any marketing agreement, license, or order, or any regulation relating to, or any provision of, or any act of the Secretary of Agriculture in connection with, any such agreement, license, or order which has been executed, issued, approved, or done under the Agricultural Adjustment Act [7 U.S.C. 601 et seq.], or any amendment thereof, but such marketing agreements, licenses, orders, regulations, provisions, and acts are expressly ratified, legalized, and confirmed.