python 3 updates

- Fix super() calls for python 3
- No need to inherit objects.
- No need for u at the start of strings
- Tidied up some brackets and f-strings too

web/pgadmin/tools/import_export/tests/test_import_export_create_job_unit_test.py

@@ -12,7 +12,7 @@ import os
 
 from pgadmin.utils.route import BaseTestGenerator
 from regression import parent_node_dict
-from pgadmin.utils import server_utils as server_utils, does_utility_exist
+from pgadmin.utils import server_utils, does_utility_exist
 from pgadmin.browser.server_groups.servers.databases.tests import utils as \
     database_utils
 from unittest.mock import patch, MagicMock