FunctionCallingHelper‘s ParameterDescription Required = false not work

[wumao]

Describe the bug
A clear and concise description of what the bug is.

[ParameterDescription(Description = "Left Parameter", Required = false)] double left,

throw error: System.Exception:“Argument 'left' not found”

Your code piece

  [FunctionDescription("Add new Widget")]
        public string AddWidgetFunction(
             [ParameterDescription(Description = "Widget  Type Parameter", Required = true)] WidgetTypeEnum widgetType,
            [ParameterDescription(Description = "Left Parameter", Required = false)] double left,
           [ParameterDescription(Description = "Top Parameter", Required = false)] double top,

           [ParameterDescription(Description = "Width Parameter", Required = false)] double width,

           [ParameterDescription(Description = "Height Parameter", Required = false)] double height
            )
        {
            return "finish";
        }
        //------------------------
          var obj = new UIFunctionCallingClass();

  var functionCall = new FunctionCall
  {
      Name = "AddWidgetFunction",
      Arguments = "{\"widgetType\":\"Rectangle\"}"
  };

  FunctionCallingHelper.CallFunction<string>(functionCall, obj);

Result
More detail about what happened when you run your code.
throw error: System.Exception:“Argument 'left' not found”

Expected behavior
A clear and concise description of what you expected to happen.
Required = false
means you can add the Arguments = "{"widgetType":"Rectangle","left":30.0}"
or Arguments = "{"widgetType":"Rectangle"}"

Screenshots
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Desktop (please complete the following information):

• OS: [e.g. Windows]
• Language [e.g. c#]
• Version [e.g. 0.0.3]

Additional context
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