By Pavel Polityuk and Tom Balmforth KYIV (Reuters) -A Russian-installed occupation official in southern Ukraine said on Thursday Moscow was likely to pull its troops from the west bank of the Dnipro River, signalling a huge retreat that, if confirmed, would be a major turning point in the war. Still, Ukrainian officials and Western analysts remained cautious about signs that Russia was abandoning the area, and there was silence from higher-ups in Moscow over what would amount to one of Russia’s most humiliating retreats so far. Kyiv said it was still fighting in the area and was wary that Mosc…