feat: Flexion channel build fixes

- Add google-services.json per-channel copy in SwitchChannel (Flexion has extra client)
- Add GooglePlay default google-services.json for fallback
- Switch Bundle Identifier per channel (Flexion → com.arkgame.ft.flexion)
- Fix FlexionSDKHelper missing BillingService import
- Fix Flexion AndroidManifest: add fullBackupContent override with flexion_backup_rules
- Add MainProcessName tools:replace to resolve gasdk/tuyoosdk manifest conflict
- Add billing:6.0.1 dependency for tuyoosdk AAR init compatibility

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

ExtraPluginCfgs/Android/flexion/AndroidManifest.xml

@@ -7,7 +7,8 @@
     <uses-permission android:name="android.permission.POST_NOTIFICATIONS"/>
     <uses-permission android:name="android.permission.READ_PHONE_STATE" />
     <application android:extractNativeLibs="true" android:name="com.unity3d.player.TYApp"
-    tools:replace="android:usesCleartextTraffic"
+    tools:replace="android:usesCleartextTraffic,android:fullBackupContent"
+    android:fullBackupContent="@xml/flexion_backup_rules"
     android:usesCleartextTraffic="true">
         <activity android:name="com.unity3d.player.TYUnityActivity"
                   android:theme="@style/UnityThemeSelector">
@@ -36,6 +37,11 @@
         <!-- 渠道标识，ChannelManager 读取此值以识别 Flexion 渠道 -->
         <meta-data android:name="CHANNEL" android:value="Flexion" />
 
+        <!-- 覆盖 gasdk 与 tuyoosdk 的 MainProcessName 冲突 -->
+        <meta-data android:name="com.sensorsdata.analytics.android.MainProcessName"
+            android:value="${applicationId}"
+            tools:replace="android:value" />
+
         <!-- Flexion SDK 应用标识，从 DropPoint 获取 -->
         <meta-data android:name="com.flexionmobile.fdk.apptoken" android:value="fishingtravel" />