Home Assistant demo server: fix demo light templates

[zehnm]

After updating Home Assistant to the latest version the light template isn't fully working anymore:

Invalid config for [light.template]: [set_white_value] is an invalid option for [light.template].
Check: light.template->lights->sitting_room_chandellier->set_white_value.
(See /config/configuration.yaml, line 89). Please check the docs at https://www.home-assistant.io/integrations/template

[zehnm]

They removed white_value: https://developers.home-assistant.io/blog/2022/08/18/light_white_value_removed/
and it was announced a while ago in the light entity description 🙈

[zehnm]

I can't figure out how to write a Home Assistant light template which allows setting the white value with the new color_mode: white settings. It's probably obvious, but I'm not alone (and the official HA light template example still uses set_white_value):

• https://community.home-assistant.io/t/update-to-2022-9-1-broke-my-light-templates/459123
• https://community.home-assistant.io/t/light-template-is-not-working/522791/3
• https://community.home-assistant.io/t/how-to-create-a-light-template-with-white-rgb-color-modes/507970
• https://community.home-assistant.io/t/light-template-cannot-change-color-mode/444424

Clarification: this is only about writing a demo light template for the included Home Assistant demo configuration in configuration.yaml.
Setting the white value with the API is done with a new command parameter white: {"service": "light.turn_on", "data": {"white":50}} (according to: home-assistant/core#51411)