tests: switch off logging

src/test/resources/logback-test.xml

@@ -6,7 +6,7 @@
             <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%X{mdc.client}] [%thread] %highlight(%-5level) %cyan(%logger{15}) - %msg%n</pattern>
         </encoder>
     </appender>
-    <root level="WARN">
+    <root level="OFF">
         <appender-ref ref="STDOUT" />
     </root>
 </configuration>