GH-1145 Fix List conversion for Function<Message<List>, ..>

Resolves #1145

Author: olegz

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java

@@ -1343,6 +1343,12 @@ private Object convertInputMessageIfNecessary(Message message, Type type) {
 				if (collectionType == itemType) {
 					return message.getPayload();
 				}
+
+				if (collectionType != null
+						&& FunctionTypeUtils.getRawType(itemType).isAssignableFrom(collectionType.getClass())
+						&& FunctionTypeUtils.isMessage(type)) {
+					return message;
+				}
 			}
 
 			Object convertedInput = message.getPayload();