Fallback to Object.class not the function type

See gh-118 (partial fix)

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

@@ -633,7 +633,7 @@ public class ContextFunctionCatalogAutoConfiguration {
 				}
 			}
 			else {
-				param = type;
+				param = Object.class;
 			}
 			return param;
 		}