Made ResultObject nullable.

Author: SharePointRadi

src/OneBitSoftware.Utilities.OperationResult/OperationResult.cs

@@ -264,7 +264,7 @@ public OperationResult(TResult resultObject) : base()
         /// <summary>
         /// Gets or sets the related result object of the operation.
         /// </summary>
-        public TResult ResultObject { get; set; }
+        public TResult? ResultObject { get; set; }
 
         /// <summary>
         /// This method will append an error with a specific `user-friendly` message to this operation result instance.