Feature: Transition sanity check to rich and improve output (#12182)

src/documents/tests/test_management_exporter.py

@@ -288,7 +288,7 @@ class TestExportImport(
             self.assertEqual(Permission.objects.count(), num_permission_objects)
             messages = check_sanity()
             # everything is alright after the test
-            self.assertEqual(len(messages), 0)
+            self.assertEqual(messages.total_issue_count, 0)
 
     def test_exporter_with_filename_format(self) -> None:
         shutil.rmtree(Path(self.dirs.media_dir) / "documents")