[in_app_purchase] fixed a memory leak error (#5358)

diff --git a/packages/in_app_purchase/in_app_purchase_storekit/CHANGELOG.md b/packages/in_app_purchase/in_app_purchase_storekit/CHANGELOG.md
index aba1d6e..365c713 100644
--- a/packages/in_app_purchase/in_app_purchase_storekit/CHANGELOG.md
+++ b/packages/in_app_purchase/in_app_purchase_storekit/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.3.0+8
+
+* Fixes a memory leak on iOS.
+
 ## 0.3.0+7
 
 * Minor fixes for new analysis options.
diff --git a/packages/in_app_purchase/in_app_purchase_storekit/ios/Classes/InAppPurchasePlugin.m b/packages/in_app_purchase/in_app_purchase_storekit/ios/Classes/InAppPurchasePlugin.m
index a580a46..d64c245 100644
--- a/packages/in_app_purchase/in_app_purchase_storekit/ios/Classes/InAppPurchasePlugin.m
+++ b/packages/in_app_purchase/in_app_purchase_storekit/ios/Classes/InAppPurchasePlugin.m
@@ -25,9 +25,6 @@
 
 // Callback channel to dart used for when a function from the payment queue delegate is triggered.
 @property(strong, nonatomic, readonly) FlutterMethodChannel *paymentQueueDelegateCallbackChannel;
-
-@property(strong, nonatomic, readonly) NSObject<FlutterTextureRegistry> *registry;
-@property(strong, nonatomic, readonly) NSObject<FlutterBinaryMessenger> *messenger;
 @property(strong, nonatomic, readonly) NSObject<FlutterPluginRegistrar> *registrar;
 
 @property(strong, nonatomic, readonly) FIAPReceiptManager *receiptManager;
@@ -57,8 +54,6 @@
 - (instancetype)initWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
   self = [self initWithReceiptManager:[FIAPReceiptManager new]];
   _registrar = registrar;
-  _registry = [registrar textures];
-  _messenger = [registrar messenger];
 
   __weak typeof(self) weakSelf = self;
   _paymentQueueHandler = [[FIAPaymentQueueHandler alloc] initWithQueue:[SKPaymentQueue defaultQueue]
@@ -347,7 +342,7 @@
   if (@available(iOS 13.0, *)) {
     _paymentQueueDelegateCallbackChannel = [FlutterMethodChannel
         methodChannelWithName:@"plugins.flutter.io/in_app_purchase_payment_queue_delegate"
-              binaryMessenger:_messenger];
+              binaryMessenger:[_registrar messenger]];
 
     _paymentQueueDelegate = [[FIAPPaymentQueueDelegate alloc]
         initWithMethodChannel:_paymentQueueDelegateCallbackChannel];
diff --git a/packages/in_app_purchase/in_app_purchase_storekit/pubspec.yaml b/packages/in_app_purchase/in_app_purchase_storekit/pubspec.yaml
index 235d491..ebd5e55 100644
--- a/packages/in_app_purchase/in_app_purchase_storekit/pubspec.yaml
+++ b/packages/in_app_purchase/in_app_purchase_storekit/pubspec.yaml
@@ -2,7 +2,7 @@
 description: An implementation for the iOS platform of the Flutter `in_app_purchase` plugin. This uses the StoreKit Framework.
 repository: https://github.com/flutter/plugins/tree/main/packages/in_app_purchase/in_app_purchase_storekit
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+in_app_purchase%22
-version: 0.3.0+7
+version: 0.3.0+8
 
 environment:
   sdk: ">=2.14.0 <3.0.0"