fix build issue

kop-common-lib/src/test/java/de/itvsh/kop/common/binaryfile/GrpcFileUploadUtilsTest.java

@@ -29,7 +29,6 @@ import static org.mockito.Mockito.*;
 
 import java.io.IOException;
 import java.io.InputStream;
-import java.util.concurrent.CompletableFuture;
 import java.util.function.BiFunction;
 import java.util.function.Function;
 
@@ -116,7 +115,7 @@ class GrpcFileUploadUtilsTest {
 			assertThat(result).isNotNull();
 		}
 
-		private CompletableFuture<TestResponseType> callService() {
+		private FileSender<TestRequestType, TestResponseType> callService() {
 			return fileSender.send();
 		}
 	}