refactor(admin-charge): QGetChargeStatusQueryDto의 currency가 null이 되지 않도록 coalesce("") 사용

src/main/kotlin/kr/co/vividnext/sodalive/admin/charge/AdminChargeStatusQueryRepository.kt

@@ -36,7 +36,7 @@ class AdminChargeStatusQueryRepository(private val queryFactory: JPAQueryFactory
                     payment.price.sum(),
                     payment.id.count(),
                     payment.paymentGateway,
-                    currency
+                    currency.coalesce("")
                 )
             )
             .from(payment)