Avoid duplicate RSocket endpoint for WebSocket

Prior to this commit, choosing a "websocket" transport for your RSocket
endpoint with `spring.rsocket.server.port` would not only expose the
endpoint on that specific port, but also on the main server.

This commit refines the auto-configuration condition to only add a route
on the main server if the separate port is not chosen.

Fixes gh-49592

Author: bclozel

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/rsocket/RSocketServerAutoConfiguration.java

@@ -148,7 +148,7 @@ static class IsReactiveWebApplication {
 
 		}
 
-		@ConditionalOnProperty(name = "spring.rsocket.server.port", matchIfMissing = true)
+		@ConditionalOnProperty(name = "spring.rsocket.server.port", havingValue = "false", matchIfMissing = true)
 		static class HasNoPortConfigured {
 
 		}

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/rsocket/RSocketServerAutoConfigurationTests.java

@@ -84,6 +84,17 @@ void shouldCreateDefaultBeansForReactiveWebApp() {
 			.run((context) -> assertThat(context).hasSingleBean(RSocketWebSocketNettyRouteProvider.class));
 	}
 
+	@Test
+	void shouldNotCreateWebSocketRouteProviderWhenDedicatedPortIsSet() {
+		reactiveWebContextRunner()
+			.withPropertyValues("spring.rsocket.server.port=0", "spring.rsocket.server.transport=websocket",
+					"spring.rsocket.server.mapping-path=/rsocket")
+			.run((context) -> {
+				assertThat(context).hasSingleBean(RSocketServerFactory.class);
+				assertThat(context).doesNotHaveBean(RSocketWebSocketNettyRouteProvider.class);
+			});
+	}
+
 	@Test
 	void shouldCreateDefaultBeansForRSocketServerWhenPortIsSet() {
 		reactiveWebContextRunner().withPropertyValues("spring.rsocket.server.port=0")