correção visita_domiciliar_tela.dart, register_citizen_screen.dart e register_individual_screen.dart

lib/models/drop_down_data_string_model.dart

@@ -6,5 +6,17 @@ class DropDownDataStringModel{
     required this.cod,
     required this.title
   });
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+          other is DropDownDataStringModel &&
+              runtimeType == other.runtimeType &&
+              cod == other.cod &&
+              title == other.title;
+
+  @override
+  int get hashCode => cod.hashCode ^ title.hashCode;
+
 }