fix(medusa): List products by type_id (#2427)

**What**
- Fixes `GET /products` in both admin and store API so they no longer accept the param `type?: string`, but instead accept `type_id?: string[]`

**Why**
- Filtering by type would never return any products as `ptyp_:id` !== `ProductType`.

**Testing**
- Added an integration test for each endpoint.

Closes CORE-695

integration-tests/api/__tests__/admin/product.js

@@ -168,6 +168,30 @@ describe("/admin/products", () => {
       }
     })
 
+    it("returns a list of products where type_id is test-type", async () => {
+      const api = useApi()
+
+      const response = await api
+        .get("/admin/products?type_id[]=test-type", {
+          headers: {
+            Authorization: "Bearer test_token",
+          },
+        })
+        .catch((err) => {
+          console.log(err)
+        })
+
+      expect(response.status).toEqual(200)
+      expect(response.data.products).toHaveLength(5)
+      expect(response.data.products).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            type_id: "test-type",
+          }),
+        ])
+      )
+    })
+
     it("doesn't expand collection and types", async () => {
       const api = useApi()
 

integration-tests/api/__tests__/store/products.js

@@ -195,6 +195,24 @@ describe("/store/products", () => {
       }
     })
 
+    it("works when filtering by type_id", async () => {
+      const api = useApi()
+
+      const response = await api.get(
+        `/store/products?type_id[]=test-type&fields=id,title,type_id`
+      )
+
+      expect(response.status).toEqual(200)
+      expect(response.data.products).toHaveLength(5)
+      expect(response.data.products).toEqual(
+        expect.arrayContaining([
+          expect.objectContaining({
+            type_id: "test-type",
+          }),
+        ])
+      )
+    })
+
     it("returns only published products", async () => {
       const api = useApi()