### Apache Airflow Provider(s)

databricks

### Versions of Apache Airflow Providers

apache-airflow-providers-databricks==1!2.0.2


### Apache Airflow version

2.1.4 (latest released)

### Operating System

Debian GNU/Linux 11 (bullseye)

### Deployment

Docker-Compose

### Deployment details

Running local deployment using Astronomer CLI

### What happened

When calling the `get_run_state` method from the `DatabricksHook`, I get the following error:

`TypeError: Object of type RunState is not JSON serializable`

I think this is due to [the method returning a RunState custom class](https://github.com/apache/airflow/blob/main/airflow/providers/databricks/hooks/databricks.py#L275) as opposed to a `str` like the rest of the methods in the databricks hook (i.e. `get_job_id`, `get_run_page_url`, etc.)

### What you expected to happen

When calling the `get_run_state` method, simply return the `result_state` or `state_message` [variables](https://github.com/apache/airflow/blob/main/airflow/providers/databricks/hooks/databricks.py#L287-L288) instead of the `RunState` class.

### How to reproduce

Create a dag that references a databricks deployment and use this task to see the error:

```
    from airflow.providers.databricks.hooks.databricks import DatabricksHook
    run_id = <insert run id from databricks ui here>

    def get_run_state(self, run_id: str):
           return self.hook.get_run_state(run_id=run_id)

    python_get_run_state = PythonOperator(
        task_id="python_get_run_state",
        python_callable=get_run_state,
        op_kwargs={
            "run_id": str(run_id)
        }
    )
```

### 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/providers/databricks/hooks/test_databricks.py
non_terminal_states = ['PENDING', 'RUNNING', 'TERMINATING']
        for state in non_terminal_states:
            run_state = RunState(state, '', '')
            assert not run_state.is_terminal
    def test_is_terminal_with_nonexistent_life_cycle_state(self):
        run_state = RunState('blah', '', '')
        with pytest.raises(AirflowException):
            run_state.is_terminal
    def test_is_successful(self):
        run_state = RunState('TERMINATED', 'SUCCESS', '')
        assert run_state.is_successful
def create_aad_token_for_resource(resource: str) -> dict:
    return {
        "token_type": "Bearer",
        "expires_in": "599",
        "ext_expires_in": "599",
        "expires_on": "1575500666",
        "not_before": "1575499766",
        "resource": resource,
        "access_token": TOKEN,
    }
class TestDatabricksHookAadToken(unittest.TestCase):
    """
    Tests for DatabricksHook when auth is done with AAD token for SP as user inside workspace.
    """
    @provide_session
    def setUp(self, session=None):