ImportError: cannot import name 'SUPERVISOR_COMMS' with dag.test()

### Apache Airflow version

3.0.2

### If "Other Airflow 2 version" selected, which one?

_No response_

### What happened?

The exception occurred when the DAG ran with `dag.test()` attempted to retrieve a variable from the API server. Some similar issues have been opened (#48554, #51062, #51316). The PRs provided as a solution (#50300, #50419) were included in 3.0.2 but did not fix the problem.

```
Exception has occurred: ImportError
cannot import name 'SUPERVISOR_COMMS' from 'airflow.sdk.execution_time.task_runner' (/workspaces/airflow/.venv/lib/python3.12/site-packages/airflow/sdk/execution_time/task_runner.py)
File "/workspaces/airflow/test.py", line 7, in
x = Variable.get("my_variable")
^^^^^^^^^^^^^^^^^^^^^^^^
ImportError: cannot import name 'SUPERVISOR_COMMS' from 'airflow.sdk.execution_time.task_runner' (/workspaces/airflow/.venv/lib/python3.12/site-packages/airflow/sdk/execution_time/task_runner.py)
```

### What you think should happen instead?

The variable should have been successfully retrieved without exceptions.

### How to reproduce

1. Set the variable: `airflow variables set my_variable my_value`
2. Run DAG:
```
import logging

from airflow import DAG
from airflow.providers.standard.operators.empty import EmptyOperator
from airflow.providers.standard.operators.python import PythonOperator
from airflow.sdk import Variable

x = Variable.get("my_variable")

def my_function(my_var: str) -> None:
logging.getLogger(__name__).info(my_var)

with DAG("test_dag") as dag:

start = EmptyOperator(task_id="start")

py_func = PythonOperator(
task_id="py_func",
python_callable=my_function,
op_kwargs={
"my_var": x
}
)

end = EmptyOperator(task_id="end")

start >> py_func >> end

if __name__ == "__main__":
dag.test()
```

### Operating System

Debian GNU/Linux 12 (bookworm)

### Versions of Apache Airflow Providers

_No response_

### Deployment

Other Docker-based deployment

### Deployment details

Extended image based on `apache/airflow:slim-3.0.2-python3.12`

### 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)

Start with the reproducer in test.py, focusing on Variable.get("my_variable") during dag.test(), and trace the ImportError for SUPERVISOR_COMMS. Review related issues #48554, #51062, and #51316 plus PRs #50300 and #50419; done means the shown DAG retrieves the variable without an ImportError on Airflow 3.0.2.

Written by the indexing model from the issue text.