Allow fallback on subclass of ProblemDetail

Closes gh-30533

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/RequestResponseBodyMethodProcessorTests.java

@@ -1,4 +1,4 @@
-/*
+`/*
  * Copyright 2002-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -374,7 +374,7 @@ class RequestResponseBodyMethodProcessorTests {
 	}
 
 	private void testProblemDetailMediaType(String expectedContentType) throws Exception {
-		ProblemDetail problemDetail = ProblemDetail.forStatus(HttpStatus.BAD_REQUEST);
+		MyProblemDetail problemDetail = new MyProblemDetail(HttpStatus.BAD_REQUEST);
 
 		this.servletRequest.setRequestURI("/path");
 
@@ -805,7 +805,7 @@ class RequestResponseBodyMethodProcessorTests {
 	}
 
 	@SuppressWarnings("ConstantConditions")
-	ProblemDetail handleAndReturnProblemDetail() {
+	MyProblemDetail handleAndReturnProblemDetail() {
 		return null;
 	}
 
@@ -821,6 +821,15 @@ class RequestResponseBodyMethodProcessorTests {
 	}
 
 
+	private static class MyProblemDetail extends ProblemDetail {
+
+		public MyProblemDetail(HttpStatus status) {
+			super(status.value());
+		}
+
+	}
+
+
 	private static abstract class MyParameterizedController<DTO extends Identifiable> {
 
 		@SuppressWarnings("unused")