fix(medusa): Support fields param in list-variants (#5053)

* fix(medusa): Support fields param in list-variants

* Create cuddly-pigs-tease.md

* address pr comments

integration-tests/api/__tests__/store/product-variants.js

@@ -379,5 +379,38 @@ describe("/store/variants", () => {
         ],
       })
     })
+
+    it("should list variants with id using fields param", async () => {
+      const api = useApi()
+
+      const response = await api
+        .get("/store/variants?fields=id&expand=&limit=1")
+        .catch((err) => console.log(err))
+
+      expect(response.data).toEqual({
+        variants: [
+          {
+            id: expect.any(String),
+            created_at: expect.any(String),
+            // tax rates, prices, and calculated prices are added regardless of fields and expand
+            calculated_price: null,
+            calculated_price_incl_tax: null,
+            calculated_tax: null,
+            original_price: null,
+            original_price_incl_tax: null,
+            original_tax: null,
+            tax_rates: null,
+            prices: expect.arrayContaining([
+              expect.objectContaining({
+                id: expect.any(String),
+                variant_id: expect.any(String),
+                created_at: expect.any(String),
+                updated_at: expect.any(String),
+              }),
+            ]),
+          },
+        ],
+      })
+    })
   })
 })