Fix: Restore task_instance_history sequence on downgrade

[vatsrahul1001]

During a rollback from Airflow 3 to Airflow 2, the task_instance_history_id_seq PostgreSQL sequence was not being recreated. This caused task_instance_history inserts to fail with NULL constraint violations since the id column had no DEFAULT value for auto-increment.

Root Cause

In the upgrade path (migration 0060), the id column is dropped:
batch_op.drop_column("id")When PostgreSQL drops a column with an associated sequence, the sequence is also dropped (due to ownership).

Testing

1. Run command breeze start-airflow --executor CeleryExecutor --backend postgres
2. Down try downgarding airflow db downgrade --to-revision e00344393f31 -y
3. Verify Seq is getting created after downgrade

• Read the Pull Request Guidelines for more information. Note: commit author/co-author name and email in commits become permanently public when merged.
• For fundamental code changes, an Airflow Improvement Proposal (AIP) is needed.
• When adding dependency, check compliance with the ASF 3rd Party License Policy.
• For significant user-facing changes create newsfragment: {pr_number}.significant.rst or {issue_number}.significant.rst, in airflow-core/newsfragments.