Update sensor.yaml - Correcting for partlyclouded and night

[chunkysteveo]

Updates to condition value for 'partlycloudy' to be set to 'partly-cloudy' for MDI icons to work, and the new met.no integration checks for night time clear weather now using sun.down, so need to check 'clear-night' to 'night', as MDI does not have clear-night icon.

[DanielHabenicht]

You could just update the map instead:

lambda: |-
      // Map weather states to MDI characters.
      std::map<std::string, std::string> weather_icon_map
        {
...
          {"partly-cloudy", "\U000F0595"},
          {"clear-night", "\U000F0594"},
        };