PAD Change test cases example (#2596)

src/tests/Microsoft.PowerFx.Interpreter.Tests.Shared/PadUntypedObjectTests.cs

@@ -589,8 +589,8 @@ namespace Microsoft.PowerFx.Interpreter.Tests
         }
 
         public override FormulaValue GetProperty(string value, FormulaType returnType)
-        {
-            return new ErrorValue(IRContext.NotInSource(returnType), new ExpressionError() { Kind = ErrorKind.InvalidArgument });
+        {
+            return FormulaValue.NewError(new ExpressionError() { Kind = ErrorKind.InvalidArgument }, returnType);
         }
     }
     #endregion