Update Samples for 3.16 (#2085)

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or adding, and why. Consider including before/after screenshots.*

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game_template/macos/Flutter/GeneratedPluginRegistrant.swift

@@ -17,7 +17,7 @@ func RegisterGeneratedPlugins(registry: FlutterPluginRegistry) {
   AudioplayersDarwinPlugin.register(with: registry.registrar(forPlugin: "AudioplayersDarwinPlugin"))
   FLTFirebaseCorePlugin.register(with: registry.registrar(forPlugin: "FLTFirebaseCorePlugin"))
   FLTFirebaseCrashlyticsPlugin.register(with: registry.registrar(forPlugin: "FLTFirebaseCrashlyticsPlugin"))
-  GamesServicesPlugin.register(with: registry.registrar(forPlugin: "GamesServicesPlugin"))
+  SwiftGamesServicesPlugin.register(with: registry.registrar(forPlugin: "SwiftGamesServicesPlugin"))
   InAppPurchasePlugin.register(with: registry.registrar(forPlugin: "InAppPurchasePlugin"))
   PathProviderPlugin.register(with: registry.registrar(forPlugin: "PathProviderPlugin"))
   SharedPreferencesPlugin.register(with: registry.registrar(forPlugin: "SharedPreferencesPlugin"))