Fix(medusa): Missing location id on fulfillments (#3462)

**What**
- include location id when creating a fulfillment
- Allow location updates to reservations without passing along quantity

**Why**
- location_id on fulfillment was null after creation

Fixes CORE-1242, CORE-1243

integration-tests/plugins/factories/simple-cart-factory.ts

@@ -23,6 +23,7 @@ export type CartFactoryData = {
   line_items?: LineItemFactoryData[]
   shipping_address?: AddressFactoryData
   shipping_methods?: ShippingMethodFactoryData[]
+  sales_channel_id?: string
 }
 
 export const simpleCartFactory = async (
@@ -52,6 +53,7 @@ export const simpleCartFactory = async (
       typeof data.email !== "undefined" ? data.email : faker.internet.email(),
     region_id: regionId,
     shipping_address_id: address.id,
+    sales_channel_id: data.sales_channel_id || null,
   })
 
   const cart = await manager.save(toSave)