### 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)

airflow/providers/databricks/hooks/databricks.py
AZURE_DEFAULT_AD_ENDPOINT = "https://login.microsoftonline.com"
AZURE_TOKEN_SERVICE_URL = "{}/{}/oauth2/token"
AZURE_METADATA_SERVICE_TOKEN_URL = "http://169.254.169.254/metadata/identity/oauth2/token"
AZURE_METADATA_SERVICE_INSTANCE_URL = "http://169.254.169.254/metadata/instance"
TOKEN_REFRESH_LEAD_TIME = 120
AZURE_MANAGEMENT_ENDPOINT = "https://management.core.windows.net/"
DEFAULT_DATABRICKS_SCOPE = "2ff814a6-3304-4ab8-85cb-cd0e6f879c1d"
class RunState:
    """Utility class for the run state concept of Databricks runs."""
    def __init__(self, life_cycle_state: str, result_state: str, state_message: str) -> None:
        self.life_cycle_state = life_cycle_state
        self.result_state = result_state
        self.state_message = state_message
    @property
    def is_terminal(self) -> bool:
        """True if the current state is a terminal state."""
        if self.life_cycle_state not in RUN_LIFE_CYCLE_STATES:
            raise AirflowException(
                (
                    'Unexpected life cycle state: {}: If the state has '
                    'been introduced recently, please check the Databricks user '
                    'guide for troubleshooting information'
                ).format(self.life_cycle_state)
            )
        return self.life_cycle_state in ('TERMINATED', 'SKIPPED', 'INTERNAL_ERROR')
    @property
    def is_successful(self) -> bool:
        """True if the result state is SUCCESS"""
        return self.result_state == 'SUCCESS'
    def __eq__(self, other: object) -> bool: