Revert "block 可以拖拽到内部，还有少量问题待解决"

This reverts commit 538898d238.

Extensions/AIStudio.Wpf.Block/Models/VarParameter.cs

@@ -1,13 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
-namespace AIStudio.Wpf.Block.Models
-{
-    public class VarParameter : IParameter
-    {
-       
-    }
-}