GH-789 Propagate AWS FunctionInvoker exceptions

They will be handled by the AWS runtime and properly reported and recorded.
Resolves #789

spring-cloud-function-samples/function-sample-aws/src/main/java/example/FunctionConfiguration.java

@@ -21,7 +21,7 @@ public class FunctionConfiguration {
 	public Function<String, String> uppercase() {
 		return value -> {
 			if (value.equals("exception")) {
-				throw new RuntimeException("Intentional exception which should result in HTTP 417");
+				throw new RuntimeException("Intentional exception");
 			}
 			else {
 				return value.toUpperCase();