Fix compile failure with PR #861 (#866)

Missing ")" in the line 607. 
This happens when you edit it directly in github browser 🤣

src/main/java/world/bentobox/bentobox/database/objects/Island.java

@@ -603,7 +603,7 @@ public class Island implements DataObject {
     @NonNull
     public List<Player> getPlayersOnIsland() {
         return Bukkit.getOnlinePlayers().stream()
-                .filter(player -> onIsland(player.getLocation())
+                .filter(player -> onIsland(player.getLocation()))
                 .collect(Collectors.toList());
     }