By Mark Trevelyan LONDON (Reuters) -Facebook owner Meta Platforms said Friday that a temporary change in its content policy, only for Ukraine, was needed to let users voice opposition to Russia’s attack, as Russia opened a criminal case after the company said it would allow posts such as “death to the Russian invaders.” Russian prosecutors asked a court to designate the U.S. tech giant as an “extremist organisation,” and the communications regulator said it would restrict access to Meta’s Instagram starting March 14. “A criminal case has been initiated … in connection with illegal calls for …