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

packages/inventory/src/services/reservation-item.ts

@@ -166,7 +166,6 @@ export default class ReservationItemService extends TransactionBaseService {
 
       const shouldUpdateLocation =
         isDefined(data.location_id) &&
-        isDefined(data.quantity) &&
         data.location_id !== item.location_id
 
       const ops: Promise<unknown>[] = []
@@ -185,7 +184,7 @@ export default class ReservationItemService extends TransactionBaseService {
             .adjustReservedQuantity(
               item.inventory_item_id,
               data.location_id!,
-              data.quantity!
+              data.quantity || item.quantity!
             )
         )
       } else if (shouldUpdateQuantity) {