Fix fatal happening after introducing as_of_date for tests

[ssenart]

RROR [main] An error occured while running Gazpar2HAWS: Traceback (most recent call last):
File "/usr/local/lib/python3.12/site-packages/gazpar2haws/main.py", line 86, in main
bridge = Bridge(config)
^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/gazpar2haws/bridge.py", line 33, in init
self._gazpar.append(Gazpar(grdf_device_config, self._homeassistant))
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/gazpar2haws/gazpar.py", line 46, in init
self._as_of_date = timezone.localize(self._as_of_date)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/pytz/tzinfo.py", line 321, in localize
raise ValueError('Not naive datetime (tzinfo is already set)')
ValueError: Not naive datetime (tzinfo is already set)
Gazpar2HAWS version: 0.1.10
An error occured while running Gazpar2HAWS: Traceback (most recent call last):
File "/usr/local/lib/python3.12/site-packages/gazpar2haws/main.py", line 86, in main
bridge = Bridge(config)
^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/gazpar2haws/bridge.py", line 33, in init
self._gazpar.append(Gazpar(grdf_device_config, self._homeassistant))
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/gazpar2haws/gazpar.py", line 46, in init
self._as_of_date = timezone.localize(self._as_of_date)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/pytz/tzinfo.py", line 321, in localize
raise ValueError('Not naive datetime (tzinfo is already set)')
ValueError: Not naive datetime (tzinfo is already set)