CeleryExecutor retries can be missing from task_instance_history, so /tries omits real attempts

### Apache Airflow version 2.11.2 ### If "Other Airflow 2 version" selected, which one? N/A ### What happened? We have multiple anonymized production incidents on Airflow 2.11.2 with `CeleryExecutor` where retry attempts that definitely ran are missing from `task_instance_history`. The visible user symptom is that the Task logs / tries UI does not show all real attempts. But the more important observation is that this is not just a UI problem: one or more retry attempts are actually absent from `task_instance_history` even though scheduler and worker logs prove those attempts executed. Observed pattern in affected runs: - the surviving `task_instance` row reflects the current or final attempt - one or more earlier retry attempts are missing from `task_instance_history` - `/tries` therefore omits those attempts because it is built from `task_instance_history` plus the current `task_instance` - in at least one case, logs for a missing attempt were still retrievable directly, which makes the UI inconsistency more confusing ### What you think should happen instead? Every retry attempt that actually executes should be preserved in `task_instance_history`. If a task reaches `deferred`, `up_for_retry`, `failed`, or another terminal transition for a given try number, that try should still exist in `task_instance_history` afterward, and `/tries` should list it. ### How to reproduce I do not yet have a minimal standalone reproducer, but the repeated field pattern is: 1. Run Airflow 2.11.2 with `CeleryExecutor` 2. Use a task that can retry, including cases that may defer and then retry again 3. Let the task execute multiple tries 4. Inspect scheduler logs for the task/run and confirm a given try number was sent to the executor and finished 5. Query `task_instance_history` for that same task/run Observed result in affected runs: - `task_instance.try_number` advances normally - some earlier try numbers below the current try are missing from `task_instance_history` - `/tries` omi…