[Fix/#367] #363 머지하며 빌드가 동작하지 않는 문제 해결 (#368)

api/src/main/kotlin/com/few/api/domain/subscription/usecase/SubscribeWorkbookUseCase.kt

@@ -86,7 +86,7 @@ class SubscribeWorkbookUseCase(
             WorkbookSubscriptionEvent(
                 workbookId = subTargetWorkbookId,
                 memberId = memberId,
-                articleDayCol = subscriptionStatus?.day ?: 1
+                articleDayCol = workbookSubscriptionHistory.subDay
             )
         )
     }