fix(logs): blocking a blocked user writes no row; one upload submit path

Follow-ups from the review of the audit log layers:

- Blocking a user who is already blocked, or unblocking one who is
  not, changes nothing and now writes no row, like any other edit
  that changes nothing.
- write_chunk takes the request instead of the user and an optional
  request; the view always had one, so the branch only tests used
  is gone and every chunk 0 goes through the same audited submit.
- Tests: a busy clone creates no job and its row carries the page's
  message; a later chunk that fails writes no submit row; libvirt
  refusing a network or pool delete is a failed row.

networks/tests/test_audit_rows.py

@@ -81,6 +81,13 @@ class NetworkRowTests(TestCase):
         self.assertIn(error, [str(m) for m in get_messages(response.wsgi_request)])
         self.assertEqual(rows(), [(f"Network lab: stop: {error}", False)])
 
+    def test_a_refused_network_delete(self):
+        error = "Requested operation is not valid: network is in use"
+        with patch("vrtManager.network.wvmNetwork.delete", side_effect=libvirt.libvirtError(error)):
+            response = self.post({"delete": ""})
+        self.assertIn(error, [str(m) for m in get_messages(response.wsgi_request)])
+        self.assertEqual(rows(), [(f"Network lab: delete: {error}", False)])
+
     def test_network_create(self):
         url = reverse("networks", args=[self.compute.id])
         self.client.post(url, {"create": "", "name": "audit-net", "forward": "nat", "subnet": "198.51.100.0/24",