Unexpected error fetching dae data: 'set-cookie'

[ScottG489]

We should more gracefully handle this error. Seems for some reason the response header didn't contain Set-Cookie:

Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/helpers/update_coordinator.py", line 315, in _async_refresh
    self.data = await self._async_update_data()
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/config/custom_components/dae/coordinator.py", line 37, in _async_update_data
    return await self.hass.async_add_executor_job(self._update)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/concurrent/futures/thread.py", line 58, in run
    result = self.fn(*self.args, **self.kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/config/custom_components/dae/coordinator.py", line 33, in _update
    return self.client.get_channel_meters()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/config/custom_components/dae/client.py", line 22, in get_channel_meters
    self.login()
  File "/config/custom_components/dae/client.py", line 39, in login
    self.auth_cookies.load(r.headers['Set-Cookie'])
                           ~~~~~~~~~^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/requests/structures.py", line 52, in __getitem__
    return self._store[key.lower()][1]
           ~~~~~~~~~~~^^^^^^^^^^^^^
KeyError: 'set-cookie'