Merge branch '3.0.x'

Closes gh-35546

Author: philwebb

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinConfigurations.java

@@ -127,7 +127,7 @@ ZipkinWebClientSender webClientSender(ZipkinProperties properties,
 	static class ReporterConfiguration {
 
 		@Bean
-		@ConditionalOnMissingBean
+		@ConditionalOnMissingBean(Reporter.class)
 		@ConditionalOnBean(Sender.class)
 		AsyncReporter<Span> spanReporter(Sender sender, BytesEncoder<Span> encoder) {
 			return AsyncReporter.builder(sender).build(encoder);

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinConfigurationsReporterConfigurationTests.java

@@ -56,10 +56,11 @@ void shouldNotSupplyReporterIfSenderIsMissing() {
 
 	@Test
 	void shouldBackOffOnCustomBeans() {
-		this.contextRunner.withUserConfiguration(CustomConfiguration.class).run((context) -> {
-			assertThat(context).hasBean("customReporter");
-			assertThat(context).hasSingleBean(Reporter.class);
-		});
+		this.contextRunner.withUserConfiguration(SenderConfiguration.class, CustomConfiguration.class)
+			.run((context) -> {
+				assertThat(context).hasBean("customReporter");
+				assertThat(context).hasSingleBean(Reporter.class);
+			});
 	}
 
 	@Configuration(proxyBeanMethods = false)