By Trevor Hunnicutt and Steve Holland WASHINGTON (Reuters) – U.S. President Joe Biden will try to rally the world against Russia’s invasion of Ukraine in a speech to the United Nations General Assembly on Wednesday, saying Moscow’s war against its neighbor violates the tenets of the U.N. charter that established the post-World War Two body. Biden departs on Tuesday to join the conclave of world leaders in New York. He will have his first in-person meeting with new British Prime Minister Liz Truss on Wednesday and participate in a summit aimed at collecting pledges to help nations battle diseas…