TF-460 Add domain layer for implement get all identities

lib/features/manage_account/domain/state/get_all_identities_state.dart

@@ -0,0 +1,22 @@
+import 'package:core/core.dart';
+import 'package:jmap_dart_client/jmap/core/state.dart';
+import 'package:jmap_dart_client/jmap/identities/identity.dart';
+
+class GetAllIdentitiesSuccess extends UIState {
+  final List<Identity>? identities;
+  final State? state;
+
+  GetAllIdentitiesSuccess(this.identities, this.state);
+
+  @override
+  List<Object?> get props => [identities, state];
+}
+
+class GetAllIdentitiesFailure extends FeatureFailure {
+  final dynamic exception;
+
+  GetAllIdentitiesFailure(this.exception);
+
+  @override
+  List<Object> get props => [exception];
+}