fix(hub): Fix property accessibility issue (#12055)

Author: azabbasi

sdk/iot/Azure.Iot.Hub.Service/src/Customized/DigitalTwinClient.cs

@@ -0,0 +1,12 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+namespace Azure.Iot.Hub.Service
+{
+    /// <summary>
+    /// The DigitalTwin service client.
+    /// </summary>
+    internal partial class DigitalTwinClient
+    {
+    }
+}