Britain's Prime Minister Boris Johnson (C) talks with members of Britain's military during a reception for the Armed Forces inside 10 Downing Street in Central London on September 18, 2019. (Photo by JOHN NGUYEN/AFP via Getty Images)BRUSSELS – A report predicts that Brexit will be “more harmful and long-lasting” for the British army and U.K.’s defense sector than for the European Union.The exhaustive study by the Warsaw Institute, a leading European think tank, warns that the U.K.’s exit from the EU means existing arrangements and defense cooperation agreements “will need to be reassessed,...…Britain's Prime Minister Boris Johnson (C) talks with members of Britain's military during a reception for the Armed Forces inside 10 Downing Street in Central London on September 18, 2019. (Photo by JOHN NGUYEN/AFP via Getty Images)BRUSSELS – A report predicts that Brexit will be “more harmful and long-lasting” for the British army and U.K.’s defense sector than for the European Union.The exhaustive study by the Warsaw Institute, a leading European think tank, warns that the U.K.’s exit from the EU means existing arrangements and defense cooperation agreements “will need to be reassessed,...WW…