MOSCOW (Reuters) -Russia said on Friday it was ready to discuss a prisoner swap with the United States in private, a day after a Russian court jailed U.S. basketball star Brittney Griner for nine years for a drugs offence. The case against Griner, a two-time Olympic gold medallist and Women’s National Basketball Association (WNBA) star, plunged her into the geopolitical maelstrom that followed Russia’s sending of troops into Ukraine in February. Russian Foreign Minister Sergei Lavrov said President Vladimir Putin and U.S. President Joe Biden had previously agreed on a diplomatic channel that s…