MORIA, Greece — In an extraordinary gesture both political and personal, Pope Francis brought 12 Syrian Muslims to Italy aboard his plane Saturday after an emotional visit to the Greek island of Lesbos, which has faced the brunt of Europe’s migration crisis. Some 3,000 migrants on Lesbos are facing possible deportation back to Turkey under a new deal with the European Union, and the uncertainty has caused heavy strains. Francis decided only a week ago to bring the three refugee families to Italy after a Vatican official suggested it. [...] after this drop, the sea will never be the same, he said of his gesture, quoting one of Mother Teresa’s phrases. The Greek island just a few miles from the Turkish coast has seen hundreds of thousands of desperate people land on its shores in the last year, fleeing war and poverty at home.