Remove unused import from known_hosts test class

Author: artembilan

spring-integration-sftp/src/test/java/org/springframework/integration/sftp/session/ResourceKnownHostsServerKeyVerifierTests.java

@@ -39,7 +39,6 @@
 import org.apache.sshd.common.util.net.SshdSocketAddress;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
-import org.junit.jupiter.api.condition.DisabledIfEnvironmentVariable;
 import org.junit.jupiter.api.condition.EnabledIf;
 import org.mockito.Mockito;