Fix IntegrationAutoConfigurationTests for Java 21

Author: mhalbritter

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/integration/IntegrationAutoConfigurationTests.java

@@ -531,6 +531,7 @@ void integrationManagementInstrumentedWithObservation() {
 	@EnabledForJreRange(min = JRE.JAVA_21)
 	void integrationVirtualThreadsEnabled() {
 		this.contextRunner.withPropertyValues("spring.threads.virtual.enabled=true")
+			.withConfiguration(AutoConfigurations.of(TaskSchedulingAutoConfiguration.class))
 			.run((context) -> assertThat(context).hasSingleBean(TaskScheduler.class)
 				.getBean(IntegrationContextUtils.TASK_SCHEDULER_BEAN_NAME, TaskScheduler.class)
 				.isInstanceOf(SimpleAsyncTaskScheduler.class)