Fix include exception handling in DefaultErrorAttributes

This commit fixes a problem with the handling of the includeException
field in DefaultErrorAttributes.

See gh-22750

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/reactive/error/DefaultErrorAttributes.java

@@ -86,7 +86,7 @@ public class DefaultErrorAttributes implements ErrorAttributes {
 	@Override
 	public Map<String, Object> getErrorAttributes(ServerRequest request, ErrorAttributeOptions options) {
 		Map<String, Object> errorAttributes = getErrorAttributes(request, options.isIncluded(Include.STACK_TRACE));
-		if (this.includeException != null) {
+		if (Boolean.TRUE.equals(this.includeException)) {
 			options = options.including(Include.EXCEPTION);
 		}
 		if (!options.isIncluded(Include.EXCEPTION)) {

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/servlet/error/DefaultErrorAttributes.java

@@ -108,7 +108,7 @@ public class DefaultErrorAttributes implements ErrorAttributes, HandlerException
 	@Override
 	public Map<String, Object> getErrorAttributes(WebRequest webRequest, ErrorAttributeOptions options) {
 		Map<String, Object> errorAttributes = getErrorAttributes(webRequest, options.isIncluded(Include.STACK_TRACE));
-		if (this.includeException != null) {
+		if (Boolean.TRUE.equals(this.includeException)) {
 			options = options.including(Include.EXCEPTION);
 		}
 		if (!options.isIncluded(Include.EXCEPTION)) {