By Andrea Shalal and David Lawder WASHINGTON (Reuters) – Western nations are preparing to stage coordinated walk-outs and other diplomatic snubs to protest against Russia’s invasion of Ukraine at Wednesday’s meeting of G20 finance ministers in Washington, their officials said. While some in Western capitals argue that Russia’s actions should mean it is excluded from global meetings altogether, that is not a view shared by others in the Group of 20 big economies, including notably China and Indonesia, which is chairing the group this year. Moscow confirmed on Tuesday Finance Minister Anton Silu…