More fixes

- Allow stock item creation for inactive parts
- Better handling of successful stock item creation
- Disable fields rather than hiding them

InvenTree/company/templates/company/supplier_part.html

@@ -322,7 +322,6 @@ $("#item-create").click(function() {
             part: {{ part.part.id }},
             supplier_part: {{ part.id }},
         },
-        reload: true,
     });
 });