Remove coupling of tests to cui (#8389)

* remove coupling of tests to cui

* all testing for PUI absolute urls

* remove overlapping test

* refactor middleware check

* move static things into global

* factor out test target

* re-add api exception

* keep using settings.js for now

src/backend/InvenTree/order/tests.py

@@ -46,6 +46,11 @@ class OrderTest(TestCase):
                 self.assertEqual(
                     order.get_absolute_url(), f'/order/purchase-order/{pk}/'
                 )
+            else:
+                self.assertEqual(
+                    order.get_absolute_url(),
+                    f'/platform/purchasing/purchase-order/{pk}',
+                )
 
             self.assertEqual(order.reference, f'PO-{pk:04d}')