Fix GatewayProxyInstPProc for AOT expectations

Turns out the AOT engine deals only with indexed constructor arguments for bean definition

* Rework `GatewayProxyInstantiationPostProcessor.processAheadOfTime()`
to populate a service interface type as an indexed ctor argument instead of generic one

Author: artembilan

spring-integration-core/src/main/java/org/springframework/integration/config/GatewayProxyInstantiationPostProcessor.java

@@ -88,7 +88,7 @@ public BeanRegistrationAotContribution processAheadOfTime(RegisteredBean registe
 		if (beanClass.isInterface() && AnnotatedElementUtils.hasAnnotation(beanClass, MessagingGateway.class)) {
 			RootBeanDefinition beanDefinition = registeredBean.getMergedBeanDefinition();
 			beanDefinition.setBeanClass(AnnotationGatewayProxyFactoryBean.class);
-			beanDefinition.getConstructorArgumentValues().addGenericArgumentValue(beanClass);
+			beanDefinition.getConstructorArgumentValues().addIndexedArgumentValue(0, beanClass);
 			beanDefinition.setTargetType(
 					ResolvableType.forClassWithGenerics(AnnotationGatewayProxyFactoryBean.class, beanClass));
 		}