TF-2667 Validate email in recipient form before send email

core/lib/domain/exceptions/address_exception.dart

@@ -0,0 +1,13 @@
+import 'package:equatable/equatable.dart';
+
+class AddressException with EquatableMixin implements Exception {
+  final String message;
+
+  AddressException(this.message);
+
+  @override
+  String toString() => message;
+
+  @override
+  List<Object> get props => [message];
+}