refactor(MissionCardComp): 重构面板显示逻辑，改用缩放控制显隐

1. 重构英雄卡牌等覆盖面板的显示逻辑，从位置滑动改为缩放动画
2. 移除默认激活面板的代码，改为按需显示
3. 优化英雄槽位的显示逻辑，默认隐藏空槽位
4. 调整UI预制体的布局参数与文本内容

assets/resources/gui/ui3.plist.meta

@@ -8212,10 +8212,10 @@
         "height": 63,
         "rawWidth": 250,
         "rawHeight": 63,
-        "borderTop": 0,
-        "borderBottom": 0,
-        "borderLeft": 0,
-        "borderRight": 0,
+        "borderTop": 27,
+        "borderBottom": 29,
+        "borderLeft": 114,
+        "borderRight": 113,
         "packable": true,
         "pixelsToUnit": 100,
         "pivotX": 0.5,