Hide complete io.micrometer.tracing package in tests

See gh-29666

Author: mhalbritter

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/observation/ObservationAutoConfigurationTests.java

@@ -62,7 +62,7 @@ class ObservationAutoConfigurationTests {
 	class NoTracingTests {
 
 		private final ApplicationContextRunner contextRunner = new ApplicationContextRunner().with(MetricsRun.simple())
-				.withClassLoader(new FilteredClassLoader(TracingObservationHandler.class))
+				.withClassLoader(new FilteredClassLoader("io.micrometer.tracing"))
 				.withConfiguration(AutoConfigurations.of(ObservationAutoConfiguration.class));
 
 		@Test