Polish RSocket Anonymous Support

Changed the DSL method name to anonymous to align with jwt.
Since basicAuthenication is deprecated, we don't need to
align with its naming convention.

Also added a since attribute to the method.

Issue gh-17132

config/src/integration-test/java/org/springframework/security/config/annotation/rsocket/AnonymousAuthenticationITests.java

@@ -121,7 +121,7 @@ public class AnonymousAuthenticationITests {
 			ReactiveAuthorizationManager<PayloadExchangeAuthorizationContext> anonymous = (authentication,
 					exchange) -> authentication.map(trustResolver::isAnonymous).map(AuthorizationDecision::new);
 			rsocket.authorizePayload((authorize) -> authorize.anyExchange().access(anonymous));
-			rsocket.anonymousAuthentication((anonymousAuthentication) -> anonymousAuthentication.disable());
+			rsocket.anonymous((anonymousAuthentication) -> anonymousAuthentication.disable());
 			return rsocket.build();
 		}
 

config/src/main/java/org/springframework/security/config/annotation/rsocket/RSocketSecurity.java

@@ -171,8 +171,9 @@ public class RSocketSecurity {
 	 * Adds anonymous authentication
 	 * @param anonymous a customizer
 	 * @return this instance
+	 * @since 7.0
 	 */
-	public RSocketSecurity anonymousAuthentication(Customizer<AnonymousAuthenticationSpec> anonymous) {
+	public RSocketSecurity anonymous(Customizer<AnonymousAuthenticationSpec> anonymous) {
 		if (this.anonymousAuthSpec == null) {
 			this.anonymousAuthSpec = new AnonymousAuthenticationSpec(this);
 		}