### Apache Airflow version

Other Airflow 2 version (please specify below)

### What happened

When running a DAG that is structured like:
```
@dag{dag_id="my_dag", default_args={"retries":0"}}
def dag():
    op = MyOperator.partial(task_id="my_task", retries=3).expand(...)
```

The following test fails:
```
    def test_retries(self) -> None:
        dag_bag = DagBag(dag_folder=DAG_FOLDER, include_examples=False)
        dag = dag_bag.dags["my_dag"]
        for task in dag.tasks:
            if "my_task" in task.task_id:
                self.assertEqual(3, task.retries) # fails - this is 0
```

When printing out `task.partial_kwargs`, and looking at how the default args and partial args are merged, it seems like the default args are always taking precedence, even though in the `partial` global function, the `retries` do get set later on with the task-level parameter value. This doesn't seem to be respected though.

### What you think should happen instead

_No response_

### How to reproduce

If you run my above unit test for a test DAG, on version 2.4.3, it should show up as a test failure.

### Operating System

OS Ventura

### Versions of Apache Airflow Providers

_No response_

### Deployment

Google Cloud Composer

### 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)

return self._dag
    @property  
    def dag(self) -> DAG:  
        """Returns the Operator's DAG if set, otherwise raises an error"""
        if self._dag:
            return self._dag
        else:
            raise AirflowException(f"Operator {self} has not been assigned to a DAG yet")
    @dag.setter
    def dag(self, dag: DAG | None):
        """
        Operators can be assigned to one DAG, one time. Repeat assignments to
        that same DAG are ok.
        """
        from airflow.models.dag import DAG
        if dag is None:
            self._dag = None
            return
        if not isinstance(dag, DAG):
            raise TypeError(f"Expected DAG; received {dag.__class__.__name__}")
        elif self.has_dag() and self.dag is not dag:
            raise AirflowException(f"The DAG assigned to {self} can not be changed.")
        if self.__from_mapped:
            pass  
        elif self.task_id not in dag.task_dict:
            dag.add_task(self)
        elif self.task_id in dag.task_dict and dag.task_dict[self.task_id] is not self:
            dag.add_task(self)
        self._dag = dag
    def has_dag(self):