By Jeff Mason PORTLAND, Ore. (Reuters) -U.S. President Joe Biden on Saturday criticized British Prime Minister Liz Truss’s original economic plan as a mistake and said he was not concerned about the strength of the soaring U.S. dollar. Truss on Friday fired her finance minister Kwasi Kwarteng and scrapped parts of their economic package after it sparked financial market turmoil, including a steep dive in the value of the pound. Biden, a Democrat, frequently criticizes conservative “trickle down” economic policies, associated in the United States with former President Ronald Reagan and Republic…