refactor(mission): 优化战斗关卡UI显示与逻辑

1.  调整MissionComp注释与战斗计时获取逻辑
2.  移除关卡波数显示中的总波数限制，只显示当前波数
3.  更新mission.prefab的UI布局与默认显示文本
4.  调整地图prefab的物体位置
5.  修改bg2动画的帧率与时长参数

assets/resources/gui/element/mission.prefab

@@ -180,7 +180,7 @@
     },
     "_lpos": {
       "__type__": "cc.Vec3",
-      "x": 0,
+      "x": -259.716,
       "y": 0,
       "z": 0
     },
@@ -271,7 +271,7 @@
     },
     "_contentSize": {
       "__type__": "cc.Size",
-      "width": 510,
+      "width": 300,
       "height": 66
     },
     "_anchorPoint": {
@@ -313,7 +313,7 @@
     },
     "_type": 1,
     "_fillType": 0,
-    "_sizeMode": 1,
+    "_sizeMode": 0,
     "_fillCenter": {
       "__type__": "cc.Vec2",
       "x": 0,
@@ -443,7 +443,7 @@
       "b": 255,
       "a": 255
     },
-    "_string": "第 1/20 波",
+    "_string": "第 1 波",
     "_horizontalAlign": 1,
     "_verticalAlign": 1,
     "_actualFontSize": 26,
@@ -821,8 +821,8 @@
     },
     "_lpos": {
       "__type__": "cc.Vec3",
-      "x": 0,
-      "y": -36.584,
+      "x": 295.012,
+      "y": 0,
       "z": 0
     },
     "_lrot": {
@@ -1110,8 +1110,8 @@
     },
     "_contentSize": {
       "__type__": "cc.Size",
-      "width": 100,
-      "height": 100
+      "width": 720,
+      "height": 50
     },
     "_anchorPoint": {
       "__type__": "cc.Vec2",
@@ -1136,11 +1136,11 @@
     "__prefab": {
       "__id__": 44
     },
-    "_alignFlags": 17,
+    "_alignFlags": 41,
     "_target": null,
     "_left": 0,
     "_right": 0,
-    "_top": 39.067999999999984,
+    "_top": 64.06799999999998,
     "_bottom": 0,
     "_horizontalCenter": 0,
     "_verticalCenter": 0,
@@ -1150,7 +1150,7 @@
     "_isAbsBottom": true,
     "_isAbsHorizontalCenter": true,
     "_isAbsVerticalCenter": true,
-    "_originalWidth": 0,
+    "_originalWidth": 100,
     "_originalHeight": 0,
     "_alignMode": 2,
     "_lockFlags": 0,
@@ -14302,7 +14302,7 @@
     "_lpos": {
       "__type__": "cc.Vec3",
       "x": 761.798,
-      "y": 640,
+      "y": 1020,
       "z": 0
     },
     "_lrot": {
@@ -14903,11 +14903,11 @@
     "__prefab": {
       "__id__": 701
     },
-    "_alignFlags": 2,
+    "_alignFlags": 1,
     "_target": null,
     "_left": 0,
     "_right": 0,
-    "_top": 448.34799999999996,
+    "_top": 200,
     "_bottom": 0,
     "_horizontalCenter": 0,
     "_verticalCenter": 0,
@@ -15377,7 +15377,7 @@
     "propertyPath": [
       "_active"
     ],
-    "value": true
+    "value": false
   },
   {
     "__type__": "CCPropertyOverrideInfo",