Clean up speedtest (#41139)

* Remove unused error string + add server list log msg

* Use more common reference texts

* Revert translation files + correct typos

homeassistant/components/speedtestdotnet/sensor.py

@@ -1,6 +1,4 @@
 """Support for Speedtest.net internet speed testing sensor."""
-import logging
-
 from homeassistant.const import ATTR_ATTRIBUTION
 from homeassistant.core import callback
 from homeassistant.helpers.restore_state import RestoreEntity
@@ -19,8 +17,6 @@ from .const import (
     SENSOR_TYPES,
 )
 
-_LOGGER = logging.getLogger(__name__)
-
 
 async def async_setup_entry(hass, config_entry, async_add_entities):
     """Set up the Speedtestdotnet sensors."""