TF-3082 Restore identity from cache

model/lib/extensions/identity_request_dto_extension.dart

@@ -0,0 +1,14 @@
+import 'package:jmap_dart_client/jmap/identities/identity.dart';
+import 'package:model/identity/identity_request_dto.dart';
+
+extension IdentityRequestDtoExtension on IdentityRequestDto {
+  Identity toIdentityWithId(IdentityId identityId) => Identity(
+    id: identityId,
+    name: name,
+    replyTo: replyTo,
+    bcc: bcc,
+    textSignature: textSignature,
+    htmlSignature: htmlSignature,
+    sortOrder: sortOrder,
+  );
+}