refactor(map): 移除技能框背景节点相关代码

1.  删除SskillBoxComp中bg_node属性和updateBgNode方法
2.  精简prefab中冗余的节点配置
3.  修复CardLiteComp的canup渲染覆盖问题

assets/resources/gui/element/sibox.prefab

@@ -472,6 +472,8 @@
       "__id__": 0
     },
     "fileId": "0609p02BxJi4U2Di/K3fcs",
+    "instance": null,
+    "targetOverrides": null,
     "nestedPrefabInstanceRoots": null
   },
   {
@@ -524,10 +526,7 @@
       "b": 255,
       "a": 255
     },
-    "_spriteFrame": {
-      "__uuid__": "cb93c900-b440-4571-91d1-7da1636e3d73@58f49",
-      "__expectedType__": "cc.SpriteFrame"
-    },
+    "_spriteFrame": null,
     "_type": 0,
     "_fillType": 0,
     "_sizeMode": 0,
@@ -1221,7 +1220,7 @@
         "__id__": 87
       }
     ],
-    "_active": true,
+    "_active": false,
     "_components": [
       {
         "__id__": 93
@@ -1673,6 +1672,8 @@
       "__id__": 0
     },
     "fileId": "70kRUgd4JHx7ic4UPHFlN9",
+    "instance": null,
+    "targetOverrides": null,
     "nestedPrefabInstanceRoots": null
   },
   {
@@ -3377,9 +3378,11 @@
       "__id__": 145
     },
     "icon_node": {
+      "__id__": 105
+    },
+    "bg_node": {
       "__id__": 2
     },
-    "bg_node": null,
     "lv_label": {
       "__id__": 124
     },