**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/hooks/tableau.py
"""
    The finish code indicates the status of the job.
    .. seealso:: https://help.tableau.com/current/api/rest_api/en-us/REST/rest_api_ref.htm#query_job
    """
    PENDING = -1
    SUCCESS = 0
    ERROR = 1
    CANCELED = 2
class TableauHook(BaseHook):
    """
    Connects to the Tableau Server Instance and allows to communicate with it.
    .. see also:: https://tableau.github.io/server-client-python/docs/
    :param site_id: The id of the site where the workbook belongs to.
        It will connect to the default site if you don't provide an id.
    :type site_id: Optional[str]
    :param tableau_conn_id: The :ref:`Tableau Connection id <howto/connection:tableau>`
        containing the credentials to authenticate to the Tableau Server.
    :type tableau_conn_id: str
    """
    conn_name_attr = 'tableau_conn_id'
    default_conn_name = 'tableau_default'
    conn_type = 'tableau'
    hook_name = 'Tableau'
    def __init__(self, site_id: Optional[str] = None, tableau_conn_id: str = default_conn_name) -> None: