Update CORS handling according to Framework changes

This commit updates CORS handling according to Framework changes
introduced via [1]. It also fixes tests according to the new behavior.

See gh-16410

[1] d27b5d0ab6.

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/web/reactive/AbstractWebFluxEndpointHandlerMapping.java

@@ -190,6 +190,11 @@ public abstract class AbstractWebFluxEndpointHandlerMapping
 				.findMethod(linksHandler.getClass(), "links", ServerWebExchange.class));
 	}
 
+	@Override
+	protected boolean hasCorsConfigurationSource(Object handler) {
+		return this.corsConfiguration != null;
+	}
+
 	@Override
 	protected CorsConfiguration initCorsConfiguration(Object handler, Method method,
 			RequestMappingInfo mapping) {

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/web/reactive/ControllerEndpointHandlerMapping.java

@@ -117,6 +117,11 @@ public class ControllerEndpointHandlerMapping extends RequestMappingHandlerMappi
 				mapping.getCustomCondition());
 	}
 
+	@Override
+	protected boolean hasCorsConfigurationSource(Object handler) {
+		return this.corsConfiguration != null;
+	}
+
 	@Override
 	protected CorsConfiguration initCorsConfiguration(Object handler, Method method,
 			RequestMappingInfo mapping) {

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/web/servlet/AbstractWebMvcEndpointHandlerMapping.java

@@ -217,6 +217,11 @@ public abstract class AbstractWebMvcEndpointHandlerMapping
 				builderConfig.useTrailingSlashMatch());
 	}
 
+	@Override
+	protected boolean hasCorsConfigurationSource(Object handler) {
+		return this.corsConfiguration != null;
+	}
+
 	@Override
 	protected CorsConfiguration initCorsConfiguration(Object handler, Method method,
 			RequestMappingInfo mapping) {

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/endpoint/web/servlet/ControllerEndpointHandlerMapping.java

@@ -118,6 +118,11 @@ public class ControllerEndpointHandlerMapping extends RequestMappingHandlerMappi
 				mapping.getCustomCondition());
 	}
 
+	@Override
+	protected boolean hasCorsConfigurationSource(Object handler) {
+		return this.corsConfiguration != null;
+	}
+
 	@Override
 	protected CorsConfiguration initCorsConfiguration(Object handler, Method method,
 			RequestMappingInfo mapping) {