BRUSSELS — EU ambassadors are poised to approve a €90 billion loan to Ukraine on Wednesday — if Russian oil transit to Hungary resumes in time. In a sign of optimism they can get the deal over the line, the Cypriot presidency of the Council of the EU put the Ukraine loan on the agenda of a meeting of the EU’s 27 ambassadors on Wednesday. If oil flows resume before then, Hungary is expected to drop its opposition and the loan will be approved, four EU diplomats, who were granted anonymity to