### Apache Airflow version

main (development)

### Operating System

macOS 11.5.2

### Versions of Apache Airflow Providers

_No response_

### Deployment

Virtualenv installation

### Deployment details

_No response_

### What happened

If your first try fails and you have retries enabled, the subsequent tries skip right to the final `next_method(**next_kwargs)` instead of starting with `execute` again.

### What you expected to happen

Like we reset things like start date, we should wipe `next_method` and `next_kwargs` so we can retry the task from the beginning.

### How to reproduce

_No response_

### Anything else

_No response_

### Are you willing to submit PR?

- [X] 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)

tests/models/test_taskinstance.py
ti.refresh_from_db()
        assert ti.state == State.FAILED
        assert ti._try_number == 4
        assert ti.try_number == 5
        assert RenderedTaskInstanceFields.get_templated_fields(ti) == expected_rendered_ti_fields
    def test_next_retry_datetime(self, dag_maker):
        delay = datetime.timedelta(seconds=30)
        max_delay = datetime.timedelta(minutes=60)
        with dag_maker(dag_id='fail_dag'):
            task = BashOperator(
                task_id='task_with_exp_backoff_and_max_delay',
                bash_command='exit 1',
                retries=3,
                retry_delay=delay,
                retry_exponential_backoff=True,
                max_retry_delay=max_delay,
            )
        ti = dag_maker.create_dagrun().task_instances[0]
        ti.task = task
        ti.end_date = pendulum.instance(timezone.utcnow())
        date = ti.next_retry_datetime()
        
        period = ti.end_date.add(seconds=30) - ti.end_date.add(seconds=15)
        assert date in period
        ti.try_number = 3
        date = ti.next_retry_datetime()
        
        period = ti.end_date.add(seconds=240) - ti.end_date.add(seconds=120)
        assert date in period
        ti.try_number = 5