TF-3685 Add integration test for case change identity in draft email

Signed-off-by: dab246 <tdvu@linagora.com>

integration_test/models/provisioning_identity.dart

@@ -0,0 +1,11 @@
+import 'package:jmap_dart_client/jmap/identities/identity.dart';
+
+class ProvisioningIdentity {
+  final Identity identity;
+  final bool isDefault;
+
+  ProvisioningIdentity({
+    required this.identity,
+    this.isDefault = false,
+  });
+}