CLAP-367 Fix: 작업 삭제 호출 시 isDeleted false 설정

Author: parkjaehak

src/main/java/clap/server/domain/model/task/Task.java

@@ -117,6 +117,7 @@ public void cancelTask(Long requesterId) {
             throw new DomainException(NOT_A_REQUESTER);
         }
         this.taskStatus = TaskStatus.TERMINATED;
+        this.isDeleted = true;
         this.finishedAt = LocalDateTime.now();
     }
 }