Migrate niko_home_control light to color_mode

[emontnemery]

Proposed change

Migrate niko_home_control light to color_mode

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• Dependency upgrade
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[epenet]

Should it not be ColorMode.BRIGHTNESS?

[emontnemery]

Setting it to ONOFF will not change the behavior.

The non-working brightness code has been there since the integration was first added, @MartinHjelmare had review comments about it which were never addressed: #18019

Maybe @NoUseFreak or @legovaer could comment?