LONDON (Reuters) – British Prime Minister Boris Johnson visits the United Arab Emirates and Saudi Arabia on Wednesday as part of efforts to secure additional oil flows and increase pressure on Russian President Vladimir Putin over Ukraine. With Britain, like much of the West, facing spiralling energy prices, Johnson is keen to encourage producers to increase output and secure other supplies to try to help consumers and reduce reliance on Russian exports. Johnson’s spokesman has said the British leader will raise human rights issues in Saudi Arabia, including the execution of 81 men, but critic…