Fix order of headers in DefaultHandlerExceptionResolver

Closes gh-26470

Author: rstoyanchev

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/support/DefaultHandlerExceptionResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -278,11 +278,11 @@ protected ModelAndView handleHttpRequestMethodNotSupported(HttpRequestMethodNotS
 	protected ModelAndView handleHttpMediaTypeNotSupported(HttpMediaTypeNotSupportedException ex,
 			HttpServletRequest request, HttpServletResponse response, @Nullable Object handler) throws IOException {
 
-		response.sendError(HttpServletResponse.SC_UNSUPPORTED_MEDIA_TYPE);
 		List<MediaType> mediaTypes = ex.getSupportedMediaTypes();
 		if (!CollectionUtils.isEmpty(mediaTypes)) {
 			response.setHeader("Accept", MediaType.toString(mediaTypes));
 		}
+		response.sendError(HttpServletResponse.SC_UNSUPPORTED_MEDIA_TYPE);
 		return new ModelAndView();
 	}