Add selected_task_ids to airflow-ctl backfill response test fixture

Author: Fury0508

airflow-ctl/tests/airflow_ctl/api/test_operations.py

@@ -551,6 +551,7 @@ class TestBackfillOperations:
         is_paused=False,
         reprocess_behavior=ReprocessBehavior.COMPLETED,
         max_active_runs=1,
+        selected_task_ids=None,
         created_at=datetime.datetime(2024, 12, 31, 23, 59, 59),
         completed_at=datetime.datetime(2025, 1, 1, 0, 0, 0),
         updated_at=datetime.datetime(2025, 1, 1, 0, 0, 0),