By Anne Kauranen and Nora Buli HELSINKI (Reuters) -Russia’s Gazprom has informed Finland it will halt flows of natural gas from Saturday morning, Gasum said on Friday, after the Finnish state-owned gas wholesaler refused to pay its Russian supplier in roubles. Gazprom Export has demanded that European countries pay for Russian gas supplies in roubles because of sanctions imposed over Moscow’s invasion of Ukraine. Most supply contracts are denominated in euros or dollars and Moscow has already cut off gas to Bulgaria and Poland last month after they refused to comply with the new payment terms….