[ISSUE] Depreciated Endpoints to Retrieve Workspaces by AccountID for Azure

[ggkenios]

Description
Endpoints for account > provisioning > workspaces are no longer supported for Azure (Only for AWS and GCP). More specifically:

• https://docs.databricks.com/api/azure/account/workspaces/list
• https://docs.databricks.com/api/azure/account/workspaces/get

Reproduction

     def get(self, workspace_id: int) -> Workspace:
        """Get a workspace.
        
        Gets information including status for a Databricks workspace, specified by ID. In the response, the
        `workspace_status` field indicates the current status. After initial workspace creation (which is
        asynchronous), make repeated `GET` requests with the workspace ID and check its status. The workspace
        becomes available when the status changes to `RUNNING`.
        
        For information about how to create a new workspace with this API **including error handling**, see
        [Create a new workspace using the Account API].
        
        This operation is available only if your account is on the E2 version of the platform or on a select
        custom plan that allows multiple workspaces per account.
        
        [Create a new workspace using the Account API]: http://docs.databricks.com/administration-guide/account-api/new-workspace.html
        
        :param workspace_id: int
          Workspace ID.
        
        :returns: :class:`Workspace`
        """

        headers = {'Accept': 'application/json', }

        res = self._api.do('GET',
                           f'/api/2.0/accounts/{self._api.account_id}/workspaces/{workspace_id}',
                           headers=headers)
        return Workspace.from_dict(res)

    def list(self) -> Iterator[Workspace]:
        """Get all workspaces.
        
        Gets a list of all workspaces associated with an account, specified by ID.
        
        This operation is available only if your account is on the E2 version of the platform or on a select
        custom plan that allows multiple workspaces per account.
        
        :returns: Iterator over :class:`Workspace`
        """

        headers = {'Accept': 'application/json', }

        res = self._api.do('GET', f'/api/2.0/accounts/{self._api.account_id}/workspaces', headers=headers)
        return [Workspace.from_dict(v) for v in res]

Expected behavior
Update the endpoint or catch the JSON decode error to let the user know that this is no longer available on Azure.

Is it a regression?
This worked a few days ago. SDK didn't change, but the endpoints are depreciated.

Debug Logs

  File "C:\Users\thxsg\.databricks\labs\ucx\lib\src\databricks\labs\ucx\account\metastores.py", line 41, in assign_metastore
    metastore_choices = self._get_all_metastores(self._get_region(workspace_id))
                                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\thxsg\.databricks\labs\ucx\lib\src\databricks\labs\ucx\account\metastores.py", line 58, in _get_region
    workspace = self._ac.workspaces.get(workspace_id)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\thxsg\.databricks\labs\ucx\state\venv\Lib\site-packages\databricks\sdk\service\provisioning.py", line 2626, in get
    res = self._api.do('GET',
          ^^^^^^^^^^^^^^^^^^^
  File "C:\Users\thxsg\.databricks\labs\ucx\state\venv\Lib\site-packages\databricks\sdk\core.py", line 171, in do
    jsonResponse = response.json()
                   ^^^^^^^^^^^^^^^
  File "C:\Users\thxsg\.databricks\labs\ucx\state\venv\Lib\site-packages\requests\models.py", line 978, in json
    raise RequestsJSONDecodeError(e.msg, e.doc, e.pos)
requests.exceptions.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

Other Information

• OS: Windows
• Version: 24H2

Additional context
Causing multiple issues working with the UCX tool.