fix(medusa): Product import - allow null product type (#2424)

**What**
- allow the product type field to be null

**How**
- in case the type is `null`, pass `undefined` as the value of type prop to product create/update services, otherwise pass an object with `{value}` which will be upserted

Co-authored-by: Oliver Windall Juhl <59018053+olivermrbl@users.noreply.github.com>

integration-tests/api/__tests__/batch-jobs/product/import.js

@@ -133,7 +133,6 @@ describe("Product import batch job", () => {
     expect(batchJob.status).toBe("completed")
 
     const productsResponse = await api.get("/admin/products", adminReqConfig)
-
     expect(productsResponse.data.count).toBe(2)
     expect(productsResponse.data.products).toEqual(
       expect.arrayContaining([
@@ -181,6 +180,7 @@ describe("Product import batch job", () => {
               ]),
             }),
           ],
+          type: null,
           images: [
             expect.objectContaining({
               url: "test-image.png",
@@ -287,6 +287,7 @@ describe("Product import batch job", () => {
               title: "Size",
             }),
           ],
+          type: expect.objectContaining({ value: "test-type" }),
           tags: [
             expect.objectContaining({
               value: "123",

integration-tests/api/__tests__/batch-jobs/product/product-import.csv

@@ -1,5 +1,5 @@
 Product id,Product Handle,Product Title,Product Subtitle,Product Description,Product Status,Product Thumbnail,Product Weight,Product Length,Product Width,Product Height,Product HS Code,Product Origin Country,Product MID Code,Product Material,Product Collection Title,Product Collection Handle,Product Type,Product Tags,Product Discountable,Product External ID,Variant id,Variant Title,Variant SKU,Variant Barcode,Variant Inventory Quantity,Variant Allow backorder,Variant Manage inventory,Variant Weight,Variant Length,Variant Width,Variant Height,Variant HS Code,Variant Origin Country,Variant MID Code,Variant Material,Price ImportLand [EUR],Price USD,Price denmark [DKK],Price Denmark [DKK],Option 1 Name,Option 1 Value,Option 2 Name,Option 2 Value,Image 1 Url
-,test-product-product-1,Test product,,"Hopper Stripes Bedding, available as duvet cover, pillow sham and sheet.\n100% organic cotton, soft and crisp to the touch. Made in Portugal.",draft,,,,,,,,,,Test collection 1,test-collection1,test-type-1,123_1,TRUE,,,Test variant,test-sku-1,test-barcode-1,10,FALSE,TRUE,,,,,,,,,1.00,1.10,1.30,,test-option-1,option 1 value red,test-option-2,option 2 value 1,test-image.png
+,test-product-product-1,Test product,,"Hopper Stripes Bedding, available as duvet cover, pillow sham and sheet.\n100% organic cotton, soft and crisp to the touch. Made in Portugal.",draft,,,,,,,,,,Test collection 1,test-collection1,,123_1,TRUE,,,Test variant,test-sku-1,test-barcode-1,10,FALSE,TRUE,,,,,,,,,1.00,1.10,1.30,,test-option-1,option 1 value red,test-option-2,option 2 value 1,test-image.png
 existing-product-id,test-product-product-2,Test product,,test-product-description,draft,test-image.png,,,,,,,,,Test collection,test-collection2,test-type,123,TRUE,,,Test variant,test-sku-2,test-barcode-2,10,FALSE,TRUE,,,,,,,,,,,,1.10,Size,Small,,,test-image.png
 existing-product-id,test-product-product-2,Test product,,test-product-description,draft,,,,,,,,,,Test collection,test-collection2,test-type,123,TRUE,,,Test variant,test-sku-3,test-barcode-3,10,FALSE,TRUE,,,,,,,,,,1.20,,,Size,Medium,,,test-image.png
-existing-product-id,test-product-product-2,Test product,,test-product-description,draft,,,,,,,,,,Test collection,test-collection2,test-type,123,TRUE,,existing-variant-id,Test variant changed,test-sku-4,test-barcode-4,10,FALSE,TRUE,,,,,,,,,,,,,Size,Large,,,test-image.png
+existing-product-id,test-product-product-2,Test product,,test-product-description,draft,,,,,,,,,,Test collection,test-collection2,test-type,123,TRUE,,existing-variant-id,Test variant changed,test-sku-4,test-barcode-4,10,FALSE,TRUE,,,,,,,,,,,,,Size,Large,,,test-image.png