Add nightlight feature flag for OasisMist 450S (LUH-O451S-WUSR)

[ttuguy421]

The OasisMist 450S (LUH-O451S-WUSR) has a controllable night light in the VeSync app, but the nightlight feature flag doesn't appear to be enabled for this model in pyvesync.

Device: LUH-O451S-WUSR (OasisMist 450S Smart Humidifier)

The VeSyncHumid200300S class has set_night_light_brightness() and the details dict includes night_light_brightness, but the OasisMist 450S model config appears to be missing 'features': ['nightlight'] that other models like the Classic 300S have.

Home Assistant's core VeSync integration recently added night light support (home-assistant/core#137544), but it only works for devices that report the night_light property. Adding the feature flag for the OasisMist 450S would enable this functionality.

Related: haext/custom_vesync#65

Would it be possible to add the nightlight feature flag for this model?

Thanks for maintaining this library!

[webdjoe]

That's strange because I actually have this device, but it does not have a night light. Can you confirm that this is the device you have: https://levoit.com/products/oasismist-smart-humidifier

[ttuguy421]

That looks almost identical to mine except where you have humidity % mine has the button for the light.