Hundreds of thousands of Iraqi Shia cleric Muqtada Al-Sadr’s followers thronged the streets of Baghdad on Friday, answering the populist leader’s call to a mass prayer in a show of strength to his political rivals. Sadr, whose party came first in a general election in October, has vowed to disband powerful Iraqi militia groups loyal to Shia Muslim Iran and to hold corrupt Iraqi politicians to account. But the mercurial leader ordered all 74 of his lawmakers – around a quarter of the parliament – to resign last month after his attempts failed to form a government free of Iran-backed parties tha…