fix(skill): 修复技能相关的显示与逻辑问题

1. 调整技能预制体的锚点和攻击偏移参数
2. 修复SkillView.ts的代码格式与导入错误
3. 补充fixed类型技能的动画结束销毁逻辑

assets/resources/game/skill/atk/atk.prefab

@@ -142,7 +142,7 @@
     "_anchorPoint": {
       "__type__": "cc.Vec2",
       "x": 0.5,
-      "y": 0
+      "y": 0.5
     },
     "_id": ""
   },
@@ -231,7 +231,7 @@
     "_anchorPoint": {
       "__type__": "cc.Vec2",
       "x": 0.5,
-      "y": 0
+      "y": 0.5
     },
     "_id": ""
   },
@@ -252,7 +252,7 @@
       "__id__": 11
     },
     "atk_x": 20,
-    "atk_y": 0,
+    "atk_y": 30,
     "_id": ""
   },
   {
@@ -314,7 +314,7 @@
     "_offset": {
       "__type__": "cc.Vec2",
       "x": 0,
-      "y": 59.9
+      "y": -0.1
     },
     "_size": {
       "__type__": "cc.Size",