Clarify which tracing components are disabled when using tracing in tests

See gh-33975

Author: mhalbritter

spring-boot-project/spring-boot-docs/src/docs/asciidoc/actuator/tracing.adoc

@@ -202,5 +202,5 @@ For the example above, setting this property to `baggage1` results in an MDC ent
 [[actuator.micrometer-tracing.tests]]
 === Tests
 
-Tracing is not auto-configured when using `@SpringBootTest`.
+Tracing components which are reporting data are not auto-configured when using `@SpringBootTest`.
 See <<features#features.testing.spring-boot-applications.tracing, the testing section>> for more details.

spring-boot-project/spring-boot-docs/src/docs/asciidoc/features/testing.adoc

@@ -266,9 +266,11 @@ If you need to export metrics to a different backend as part of an integration t
 
 [[features.testing.spring-boot-applications.tracing]]
 ==== Using Tracing
-Regardless of your classpath, tracing is not auto-configured when using `@SpringBootTest`.
+Regardless of your classpath, tracing components which are reporting data are not auto-configured when using `@SpringBootTest`.
 
-If you need tracing as part of an integration test, annotate it with `@AutoConfigureObservability`.
+If you need those components as part of an integration test, annotate the test with `@AutoConfigureObservability`.
+
+If you have created your own reporting components (e.g. a custom `SpanExporter` or `SpanHandler`) and you don't want them to be active in tests, you can use the `@ConditionalOnEnabledTracing` annotation to disable them.