Tighten up multi-valued inputs to "lite" HTTP endpoint

If the user function is single valued but the input is an array,
we should output an array (just like the full webflux version).

spring-cloud-function-web/src/test/java/org/springframework/cloud/function/test/PojoTests.java

@@ -44,11 +44,17 @@ public class PojoTests {
 	private WebTestClient client;
 
 	@Test
-	public void words() throws Exception {
+	public void single() throws Exception {
 		client.post().uri("/").body(Mono.just("{\"value\":\"foo\"}"), String.class).exchange()
 				.expectStatus().isOk().expectBody(String.class).isEqualTo("{\"value\":\"FOO\"}");
 	}
 
+	@Test
+	public void multiple() throws Exception {
+		client.post().uri("/").body(Mono.just("[{\"value\":\"foo\"},{\"value\":\"bar\"}]"), String.class).exchange()
+				.expectStatus().isOk().expectBody(String.class).isEqualTo("[{\"value\":\"FOO\"},{\"value\":\"BAR\"}]");
+	}
+
 	@SpringBootConfiguration
 	protected static class TestConfiguration implements Function<Foo, Foo> {
 		@Override