Minor improvements for internal system notifications

application/src/main/java/org/thingsboard/server/service/notification/DefaultNotificationCenter.java

@@ -207,7 +207,7 @@ public class DefaultNotificationCenter extends AbstractSubscriptionService imple
                 try {
                     processForTarget(target, ctx);
                 } catch (Exception e) {
-                    log.error("[{}] Failed to process notification request for target {}", requestId, target.getId());
+                    log.error("[{}] Failed to process notification request for target {}", requestId, target.getId(), e);
                 }
             }
             log.debug("[{}] Notification request processing is finished", requestId);

application/src/test/java/org/thingsboard/server/service/notification/NotificationApiTest.java

@@ -619,7 +619,6 @@ public class NotificationApiTest extends AbstractNotificationApiTest {
         Notification notification = getAnotherWsClient().getLastDataUpdate().getUpdate();
         assertThat(notification.getSubject()).isEqualTo(expectedNotification.getSubject());
         assertThat(notification.getText()).isEqualTo(expectedNotification.getText());
-        System.err.println(notification);
     }
 
     @Test