TF-48 Implement save email address to local storage

lib/features/composer/domain/state/save_email_address_state.dart

@@ -0,0 +1,18 @@
+import 'package:core/core.dart';
+
+class SaveEmailAddressSuccess extends UIState {
+
+  SaveEmailAddressSuccess();
+
+  @override
+  List<Object?> get props => [];
+}
+
+class SaveEmailAddressFailure extends FeatureFailure {
+  final exception;
+
+  SaveEmailAddressFailure(this.exception);
+
+  @override
+  List<Object> get props => [exception];
+}