BERLIN — Amnesty International says a plan by religious leaders to visit the Greek island of Lesbos was a “golden opportunity to expose the disturbing plight of thousands of refugees and migrants arbitrarily detained there since the ill-begotten EU-Turkey deal came into force on 20 March.” Gauri van Gulik, deputy director for Europe at Amnesty International, called on the pope to “speak out about the violations, fear and uncertainty suffered by thousands of refugees and migrants trapped in limbo on Lesbos and elsewhere in Greece.”