fix(test): mock does_utility_exist in maintenance accept-valid tests

MaintenanceInputValidationAcceptsValidTest asserted batch_process_mock
was called, but the route short-circuits with success=0 (HTTP 200)
when does_utility_exist() returns a missing-binary error. On Windows
CI psql.exe is not at the path pgAdmin probes, so BatchProcess was
never reached and the five 'accepted' scenarios failed with
'AssertionError: False is not true'. Stub does_utility_exist to None
in this test so it focuses on input-validation acceptance, not on the
runtime PostgreSQL binary layout.

web/pgadmin/tools/maintenance/tests/test_maintenance_input_validation.py

@@ -186,13 +186,19 @@ class MaintenanceInputValidationAcceptsValidTest(BaseTestGenerator):
                           vacuum_parallel='1024', verbose=True))),
     ]
 
+    @patch('pgadmin.tools.maintenance.does_utility_exist')
     @patch('pgadmin.tools.maintenance.Server')
     @patch('pgadmin.tools.maintenance.Message')
     @patch('pgadmin.tools.maintenance.BatchProcess')
     @patch('pgadmin.utils.driver.{0}.server_manager.ServerManager.'
            'export_password_env'.format(PG_DEFAULT_DRIVER))
     def runTest(self, export_password_env_mock, batch_process_mock,
-                message_mock, server_mock):
+                message_mock, server_mock, does_utility_exist_mock):
+        # The route short-circuits with success=0 when the psql binary
+        # is missing on disk; on Windows CI the binary is not at the
+        # path pgAdmin expects, so stub the check out to keep this test
+        # focused on input validation behavior.
+        does_utility_exist_mock.return_value = None
         self.server_id = parent_node_dict["database"][-1]["server_id"]
         self.db_id = parent_node_dict["database"][-1]["db_id"]
         url = MAINTENANCE_URL.format(self.server_id, self.db_id)