By Dan Weil It owes $150 billion for foreign-currency bonds. Russia has pledged to pay them back, but in rubles, given the West’s sanctions. Last week, Fitch Ratings lowered its rating on Russia’s long-term foreign currency debt, “reflect[ing] Fitch’s view that a sovereign default is imminent.” Russia may validate Fitch’s warning Wednesday. That’s the due date for the government to make $117 million in interest payments on dollar bonds. It has a 30-day grace period to pay, but can be declared in default before then. Russian officials said the government will keep repaying its debt, including w…