### 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
host = self.hook._parse_host(HOST)
        assert host == HOST
    def test_parse_host_with_scheme(self):
        host = self.hook._parse_host(HOST_WITH_SCHEME)
        assert host == HOST
    def test_init_bad_retry_limit(self):
        with pytest.raises(ValueError):
            DatabricksHook(retry_limit=0)
    def test_do_api_call_retries_with_retryable_error(self):
        for exception in [
            requests_exceptions.ConnectionError,
            requests_exceptions.SSLError,
            requests_exceptions.Timeout,
            requests_exceptions.ConnectTimeout,
            requests_exceptions.HTTPError,
        ]:
            with mock.patch('airflow.providers.databricks.hooks.databricks.requests') as mock_requests:
                with mock.patch.object(self.hook.log, 'error') as mock_errors:
                    setup_mock_requests(mock_requests, exception)
                    with pytest.raises(AirflowException):
                        self.hook._do_api_call(SUBMIT_RUN_ENDPOINT, {})
                    assert mock_errors.call_count == self.hook.retry_limit
    @mock.patch('airflow.providers.databricks.hooks.databricks.requests')
    def test_do_api_call_does_not_retry_with_non_retryable_error(self, mock_requests):