### Apache Airflow version

main (development)

### What happened

It seems [this](https://github.com/apache/airflow/commit/e16207409998b38b91c1f1697557d5c229ed32d1) commit has made the task instance execution date disappear from the task instance tooltip completely:
![image](https://github.com/apache/airflow/assets/18099224/62c9fec5-9e02-4319-93b9-197d25a8b027)
Note the missing `Run: <execution date>` between Task_id and Run_id.
I think there's a problem with the task instance execution date, because it's always `undefined`. In an older version of Airflow (2.4.3), I can see that the tooltip always shows the **current** datetime instead of the actual execution date, which is what the author of the commit identified in the first place I think.

### What you think should happen instead

The tooltip should properly show the task instance's execution date, not the current datetime (or nothing). There's a deeper problem here that causes `ti.execution_date` to be `undefined`.

### How to reproduce

Run the main branch of Airflow, with a simple DAG that finishes a run successfully. Go to the Graph view of a DAG and hover over any completed task with the mouse.

### Operating System

Ubuntu 22.04

### Versions of Apache Airflow Providers

_No response_

### Deployment

Virtualenv installation

### Deployment details

_No response_

### Anything else

_No response_

### Are you willing to submit PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

dag_run_conf: Any, *, json_encoder: type[json.JSONEncoder] = json.JSONEncoder
) -> tuple[str | None, bool]:
    conf: str | None = None
    conf_is_json: bool = False
    if isinstance(dag_run_conf, str):
        conf = dag_run_conf
    elif isinstance(dag_run_conf, (dict, list)) and any(dag_run_conf):
        conf = json.dumps(dag_run_conf, sort_keys=True, cls=json_encoder, ensure_ascii=False)
        conf_is_json = True
    return conf, conf_is_json
def encode_dag_run(