### 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
"""
        Utility function to perform an API call with retries
        :param endpoint_info: Tuple of method and endpoint
        :type endpoint_info: tuple[string, string]
        :param json: Parameters for this API call.
        :type json: dict
        :return: If the api call returns a OK status code,
            this function returns the response in JSON. Otherwise,
            we throw an AirflowException.
        :rtype: dict
        """
        method, endpoint = endpoint_info
        self.databricks_conn = self.get_connection(self.databricks_conn_id)
        headers = USER_AGENT_HEADER.copy()
        if 'host' in self.databricks_conn.extra_dejson:
            host = self._parse_host(self.databricks_conn.extra_dejson['host'])
        else:
            host = self.databricks_conn.host
        if 'token' in self.databricks_conn.extra_dejson:
            self.log.info(
                'Using token auth. For security reasons, please set token in Password field instead of extra'
            )
            auth = _TokenAuth(self.databricks_conn.extra_dejson['token'])
        elif not self.databricks_conn.login and self.databricks_conn.password:
            self.log.info('Using token auth.')
            auth = _TokenAuth(self.databricks_conn.password)
        elif 'azure_tenant_id' in self.databricks_conn.extra_dejson:
            if self.databricks_conn.login == "" or self.databricks_conn.password == "":
                raise AirflowException("Azure SPN credentials aren't provided")