Add Pain00700106Builder and associated tests for Customer Payment Reversal V06

- Implemented Pain00700106Builder for constructing and serializing ISO 20022 pain.007.001.06 messages.
- Added methods for setting group headers, original group information, and payment instructions.
- Included validation for required fields and support for fluent API design.
- Created unit tests for MessageBuilderFactory to ensure proper registration of Pain00700106Builder.
- Developed comprehensive tests for Pain00700106Builder covering all functionalities and edge cases.
- Ensured XML serialization capabilities and validation of constructed documents.

Author: cleilson pereira

Iso20022Library.Application/Builders/MessageBuilderFactory.cs

@@ -43,7 +43,8 @@ public class MessageBuilderFactory
         { MessageType.Pain00200109, () => new Pain.Pain00200109Builder() },
         { MessageType.Pain00200110, () => new Pain.Pain00200110Builder() },
         { MessageType.Pain00700103, () => new Pain00700103Builder() },
-        { MessageType.Pain00700105, () => new Pain00700105Builder() }
+        { MessageType.Pain00700105, () => new Pain00700105Builder() },
+        { MessageType.Pain00700106, () => new Pain00700106Builder() }
     };
 
     /// <summary>