increase code readability (#3096)

* increase code readability

* fix syntax error

* remove unused imports

spring-cloud-gateway-server-mvc/src/main/java/org/springframework/cloud/gateway/server/mvc/filter/RetryFilterFunctions.java

@@ -22,7 +22,6 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
-import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.TimeoutException;
 import java.util.function.Consumer;
@@ -71,9 +70,8 @@ public abstract class RetryFilterFunctions {
 	}
 
 	private static boolean isRetryableStatusCode(HttpStatusCode httpStatus, RetryConfig config) {
-		Optional<HttpStatus.Series> seriesMatches = config.getSeries().stream()
-				.filter(series -> HttpStatus.Series.resolve(httpStatus.value()) == series).findFirst();
-		return seriesMatches.isPresent();
+		return config.getSeries().stream()
+				.anyMatch(series -> HttpStatus.Series.resolve(httpStatus.value()) == series);
 	}
 
 	public static class HttpStatusRetryPolicy extends NeverRetryPolicy {