fix(medusa): Remove duplicate DiscountRuleType import (#1699)

packages/medusa/src/services/cart.ts

@@ -3,7 +3,6 @@ import { MedusaError, Validator } from "medusa-core-utils"
 import { DeepPartial, EntityManager, In } from "typeorm"
 import { TransactionBaseService } from "../interfaces"
 import { IPriceSelectionStrategy } from "../interfaces/price-selection-strategy"
-import { DiscountRuleType } from "../models"
 import { Address } from "../models/address"
 import { Cart } from "../models/cart"
 import { CustomShippingOption } from "../models/custom-shipping-option"