Feat(medusa, medusa-js, medusa-react): Include sales channels in related queries as an optional expand parameter (#1816)

**What**
- Add `transformQuery` to get endpoints for product, order and cart
  - ensure that the default relations (when getting a singular entity) includes sales channels when enabled
- Add `EmptyQueryParams` class in common types to prevent query parameters while using `transformQuery`
- update product-, order- and cartFactory to include sales channels if provided
- remove `packages/medusa/src/controllers/products/admin-list-products.ts`

**Testing** 
- expands sales channel for single order
- expands sales channels for orders with expand parameter 
- returns single product with sales channel 
- expands sales channels for products with expand parameter
- returns cart with sales channel for single cart

Fixes CORE-293

Co-authored-by: Sebastian Rindom <7554214+srindom@users.noreply.github.com>
Co-authored-by: Adrien de Peretti <25098370+adrien2p@users.noreply.github.com>

packages/medusa/src/controllers/products/admin-list-products.ts

@@ -1,94 +0,0 @@
-import { AwilixContainer } from "awilix"
-import { AdminProductsListRes } from "../../api"
-import { pickBy } from "lodash"
-import { MedusaError } from "medusa-core-utils"
-import { Product } from "../../models/product"
-import { ProductService, PricingService } from "../../services"
-import { getListConfig } from "../../utils/get-query-config"
-import { FilterableProductProps } from "../../types/product"
-import { PricedProduct } from "../../types/pricing"
-
-type ListContext = {
-  limit: number
-  offset: number
-  order?: string
-  fields?: string
-  expand?: string
-  allowedFields?: string[]
-  defaultFields?: (keyof Product)[]
-  defaultRelations?: string[]
-}
-
-const listAndCount = async (
-  scope: AwilixContainer,
-  query: FilterableProductProps,
-  body?: object,
-  context: ListContext = { limit: 50, offset: 0 }
-): Promise<AdminProductsListRes> => {
-  const { limit, offset, allowedFields, defaultFields, defaultRelations } =
-    context
-
-  const productService: ProductService = scope.resolve("productService")
-  const pricingService: PricingService = scope.resolve("pricingService")
-  let includeFields: (keyof Product)[] | undefined
-  if (context.fields) {
-    includeFields = context.fields.split(",") as (keyof Product)[]
-  }
-
-  let expandFields: string[] | undefined
-  if (context.expand) {
-    expandFields = context.expand.split(",")
-  }
-
-  let orderBy: { [k: symbol]: "DESC" | "ASC" } | undefined
-  if (typeof context.order !== "undefined") {
-    let orderField = context.order
-    if (context.order.startsWith("-")) {
-      const [, field] = context.order.split("-")
-      orderField = field
-      orderBy = { [field]: "DESC" }
-    } else {
-      orderBy = { [context.order]: "ASC" }
-    }
-
-    if (!(allowedFields || []).includes(orderField)) {
-      throw new MedusaError(
-        MedusaError.Types.INVALID_DATA,
-        "Order field must be a valid product field"
-      )
-    }
-  }
-
-  const listConfig = getListConfig<Product>(
-    defaultFields ?? [],
-    defaultRelations ?? [],
-    includeFields,
-    expandFields,
-    limit,
-    offset,
-    orderBy
-  )
-
-  const [rawProducts, count] = await productService.listAndCount(
-    pickBy(query, (val) => typeof val !== "undefined"),
-    listConfig
-  )
-
-  let products: (Product | PricedProduct)[] = rawProducts
-
-  const includesPricing = ["variants", "variants.prices"].every((relation) =>
-    listConfig?.relations?.includes(relation)
-  )
-  if (includesPricing) {
-    products = await pricingService.setProductPrices(rawProducts)
-  }
-
-  return {
-    products,
-    count,
-    offset,
-    limit,
-  }
-}
-
-export default listAndCount