优化ReadyToWorking逻辑

DeedyDesigner/Deedy.Activity/IElement.cs

@@ -72,6 +72,8 @@ namespace Deedy.Activity
         public new void ReadyToWorking(IElement? element = null, Output? output = null)
         {
             this.Help_BuildParamMapping(output);
+            if (element is ICombinedElement combinedElement)
+                combinedElement.Help_CombineElements();
 
             this.LinkTo(element);
             if (this is IContainerElement container)