Revert "block 可以拖拽到内部，还有少量问题待解决"

This reverts commit 538898d238.

AIStudio.Wpf.DiagramDesigner/Controls/BlockConnector.cs

@@ -1,33 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.ComponentModel;
-using System.Windows;
-using System.Windows.Controls;
-using System.Windows.Documents;
-using System.Windows.Input;
-using System.Windows.Media;
-
-namespace AIStudio.Wpf.DiagramDesigner
-{
-    public class BlockConnector : ContentControl
-    {
-        public ConnectorOrientation Orientation { get; set; }
-
-        public ConnectorInfoBase Info
-        {
-            get
-            {
-                if (Content is ConnectorInfoBase connectorInfo)
-                    return connectorInfo;
-
-                return this.DataContext as ConnectorInfoBase;
-            }
-        }
-
-    }
-
-    public class BlockBorder : Border
-    {
-    }
-
-}