Improve Sales Order UX: Stock Location, Customer Filtering & Enhanced List View (#756)

* feat(sales-order): Improve UX with location display, customer filtering, and enhanced list

- Show stock location when selecting items to allocate in sales orders
- Filter inactive customers from customer selection dropdown
- Display customer name and order total in sales order list view

These changes improve the day-to-day usability for warehouse and field staff
by providing more context in key workflows without requiring extra navigation.

* Format code

lib/api_form.dart

@@ -732,6 +732,7 @@ class APIFormField {
 
         return ListTile(
           title: Text(item.partName),
+          subtitle: Text(item.locationPathString),
           leading: InvenTreeAPI().getThumbnail(item.partThumbnail),
           trailing: Text(item.quantityString()),
         );