feat (orders): add guard if parents are done, cant create child

internal/domain/main-entities/mcu-order-sub-item/entity.go

@@ -17,3 +17,7 @@ type McuOrderSubItem struct {
 	Result          *string            `json:"result"`
 	Status_Code     erc.DataStatusCode `json:"status_code"`
 }
+
+func (d McuOrderSubItem) IsCompleted() bool {
+	return d.Status_Code == erc.DSCDone
+}