**Apache Airflow version**: 2.0.1

**What happened**:

The operator fails at the last step, after successfully refreshing the workbook with this error:
```
tableauserverclient.server.endpoint.exceptions.ServerResponseError: 

        401002: Unauthorized Access
                Invalid authentication credentials were provided.
```

**What you expected to happen**:
It should not fail, like when we use the username/password authentication method (instead of personal_access_token)

<!-- What do you think went wrong? -->

Tableau server does not allow concurrent connections when using personal_access_token https://github.com/tableau/server-client-python/issues/717
The solution would be redesigning completely the operator to only call the hook once.
My quick fix was to edit this in TableauHook:

```
    def __exit__(self, exc_type: Any, exc_val: Any, exc_tb: Any) -> None:
        pass
```

**How to reproduce it**:

Run this operator TableauRefreshWorkbookOperator using Tableau personal_access_token authentication (token_name, personal_access_token).

airflow/providers/tableau/sensors/tableau_job_status.py
self,
        *,
        job_id: str,
        site_id: Optional[str] = None,
        tableau_conn_id: str = 'tableau_default',
        **kwargs,
    ) -> None:
        super().__init__(**kwargs)
        self.tableau_conn_id = tableau_conn_id
        self.job_id = job_id
        self.site_id = site_id
    def poke(self, context: dict) -> bool:
        """
        Pokes until the job has successfully finished.
        :param context: The task context during execution.
        :type context: dict
        :return: True if it succeeded and False if not.
        :rtype: bool
        """
        with TableauHook(self.site_id, self.tableau_conn_id) as tableau_hook:
            finish_code = TableauJobFinishCode(
                int(tableau_hook.server.jobs.get_by_id(self.job_id).finish_code)
            )
            self.log.info('Current finishCode is %s (%s)', finish_code.name, finish_code.value)
            if finish_code in [TableauJobFinishCode.ERROR, TableauJobFinishCode.CANCELED]:
                raise TableauJobFailedException('The Tableau Refresh Workbook Job failed!')
            return finish_code == TableauJobFinishCode.SUCCESS