refactor: FlexionSDKHelper 迁移至 ExtraPluginCfgs + 构建配置更新

- 删除 tysdk/Plugins/Android 下的 FlexionSDKHelper（已迁移至 ExtraPluginCfgs/flexion）
- 更新 AndroidManifest/mainTemplate.gradle/settingsTemplate.gradle 配置
- 更新 ChannelHelpers/ConfigManager 渠道配置
- 更新 tuyoosdk AAR 和 google-services.json

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

sdk-intergration/Packages/tysdk/Plugins/Android/ChannelHelpers.java

@@ -1,20 +1,13 @@
 package com.unity3d.player;
 
 public class ChannelHelpers {
-    
-    public static final String CHANNEL = "Flexion";
+    public static final String CHANNEL = "GooglePlay";
 
     static void register() {
-        SDKManager.registerHelper(new FlexionSDKHelper());
+        // GooglePlay uses default behavior, no additional SDKHelper
     }
 
-
-    // Flexion provides price in micros and currency code, so no normalization needed
-    // 支付的变化，可能会修改这里
     public static String normalizeSkuList(String msg) {
         return msg;
     }
-    
-    
-    //public SDKExtBuilder;
 }