Push deployer configuration out of autoconfig

It tends to pop back into function apps where it is not needed
otherwise. Users that want to use the library need to import
the FunctionConfiguration directly using the
@EnableFunctionDeployer convenience annotation..

spring-cloud-function-web/src/main/java/org/springframework/cloud/function/web/flux/request/FluxHandlerMethodArgumentResolver.java

@@ -99,10 +99,10 @@ public class FluxHandlerMethodArgumentResolver
 				body = null;
 			}
 			else {
-				try {
+				if (json.startsWith("[")) {
 					body = mapper.toList(json, type);
 				}
-				catch (IllegalArgumentException e) {
+				else {
 					nativeRequest.setAttribute(WebRequestConstants.INPUT_SINGLE, true);
 					body = Arrays.asList(mapper.toSingle(json, type));
 				}