Handle ResponseStatusException thrown by MVC functional endpoints

Prior to this commit, exceptions thrown by MVC functional handlers would
not be considered by `ExceptionHandlerExceptionResolver`. This means
that common exceptions would not be handled consistently between
annotated and functional handlers. This is true, for example, for all
`ProblemDetails`-related exception handling.

While MVC functional and annotation models are separate concepts,
WebFlux has a different error handling model that processes all
exceptions in a central place.

This commit ensures that `ExceptionHandlerExceptionResolver` considers
exceptions thrown by handlers of type `HandlerFunction<?>` and processes
them accordingly.

Closes gh-32689

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

@@ -60,6 +60,8 @@ import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
 import org.springframework.web.servlet.DispatcherServlet;
 import org.springframework.web.servlet.FlashMap;
 import org.springframework.web.servlet.ModelAndView;
+import org.springframework.web.servlet.function.HandlerFunction;
+import org.springframework.web.servlet.function.ServerResponse;
 import org.springframework.web.servlet.mvc.support.RedirectAttributes;
 import org.springframework.web.servlet.resource.ResourceHttpRequestHandler;
 import org.springframework.web.testfixture.servlet.MockHttpServletRequest;
@@ -82,6 +84,8 @@ import static org.mockito.Mockito.mock;
 @SuppressWarnings("unused")
 class ExceptionHandlerExceptionResolverTests {
 
+	//TODO
+
 	private static int DEFAULT_RESOLVER_COUNT;
 
 	private static int DEFAULT_HANDLER_COUNT;
@@ -255,6 +259,19 @@ class ExceptionHandlerExceptionResolverTests {
 		assertExceptionHandledAsBody(mav, "AnotherTestExceptionResolver: IllegalAccessException");
 	}
 
+	@Test
+	void resolveExceptionGlobalHandlerForHandlerFunction() throws Exception {
+		loadConfiguration(MyConfig.class);
+
+		IllegalAccessException ex = new IllegalAccessException();
+		HandlerFunction<ServerResponse> handlerFunction = req -> {
+			throw new IllegalAccessException();
+		};
+		ModelAndView mav = this.resolver.resolveException(this.request, this.response, handlerFunction, ex);
+
+		assertExceptionHandledAsBody(mav, "AnotherTestExceptionResolver: IllegalAccessException");
+	}
+
 	@Test
 	void resolveExceptionGlobalHandlerOrdered() throws Exception {
 		loadConfiguration(MyConfig.class);