Fix Checkstyle violation

Author: artembilan

spring-integration-core/src/test/java/org/springframework/integration/support/management/graph/IntegrationGraphServerTests.java

@@ -74,7 +74,6 @@
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationFeature;
-
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
 import net.minidev.json.JSONArray;