refactor tests for new events

src/main/java/mops/gruppen2/domain/event/DeleteUserEvent.java

@@ -6,8 +6,7 @@ import lombok.*;
  * Entfernt ein einzelnes Mitglied einer Gruppe.
  */
 @Getter
-public class DeleteUserEvent extends Event {
-
+public class DeleteUserEvent extends Event { 
     public DeleteUserEvent(Long event_id, Long group_id, String user_id) {
         super(event_id, group_id, user_id);
     }