fix(gui): 调整多个UI预制件的布局参数

1. 修正hero.prefab中多个节点的y轴位置与布局边界值
2. 调整sibox.prefab的节点位置、内容尺寸与字体大小
3. 移除sibox.prefab中冗余的bg_node引用

assets/resources/gui/element/heros.prefab

@@ -1394,7 +1394,7 @@
     "_lpos": {
       "__type__": "cc.Vec3",
       "x": 0,
-      "y": -2.252,
+      "y": 74.047,
       "z": 0
     },
     "_lrot": {
@@ -2226,7 +2226,7 @@
     "_lpos": {
       "__type__": "cc.Vec3",
       "x": 0,
-      "y": -132.818,
+      "y": -108.162,
       "z": 0
     },
     "_lrot": {
@@ -10985,7 +10985,7 @@
     "_lpos": {
       "__type__": "cc.Vec3",
       "x": 0,
-      "y": -218.836,
+      "y": -199.317,
       "z": 0
     },
     "_lrot": {
@@ -11489,8 +11489,8 @@
     "_target": null,
     "_left": 30,
     "_right": 30,
-    "_top": 553.836,
-    "_bottom": 116.16400000000002,
+    "_top": 534.317,
+    "_bottom": 135.68299999999996,
     "_horizontalCenter": 0,
     "_verticalCenter": 0,
     "_isAbsLeft": true,

assets/resources/gui/element/sibox.prefab

@@ -2865,8 +2865,8 @@
     },
     "_lpos": {
       "__type__": "cc.Vec3",
-      "x": 32.887,
-      "y": -29.289,
+      "x": 0,
+      "y": -39.737,
       "z": 0
     },
     "_lrot": {
@@ -2906,7 +2906,7 @@
     },
     "_contentSize": {
       "__type__": "cc.Size",
-      "width": 20.628952026367188,
+      "width": 15.123046875,
       "height": 54.4
     },
     "_anchorPoint": {
@@ -2945,8 +2945,8 @@
     "_string": "1",
     "_horizontalAlign": 1,
     "_verticalAlign": 1,
-    "_actualFontSize": 29.9,
-    "_fontSize": 29.9,
+    "_actualFontSize": 20,
+    "_fontSize": 20,
     "_fontFamily": "Arial",
     "_lineHeight": 40,
     "_overflow": 0,
@@ -3380,9 +3380,6 @@
     "icon_node": {
       "__id__": 105
     },
-    "bg_node": {
-      "__id__": 2
-    },
     "lv_label": {
       "__id__": 124
     },