KYIV/ZAPORIZHZHIA, Ukraine, March 22 (Reuters) - Russia blasted an apartment block in Ukraine with missiles on Wednesday and swarmed cities with drone attacks overnight, in a display of force as President Vladimir Putin bid farewell to his visiting "dear friend" and Chinese leader Xi Jinping. China has proposed a peace plan for Ukraine that the West largely dismisses as vague at best, and at worst a ploy to buy time for Putin to regroup his forces. Ukraine's military General Staff agreed, saying Russia's offensive potential in Bakhmut was declining