Migrate xiaomi_miio light to color_mode

[emontnemery]

Proposed change

Migrate `xiaomi_miio light to color_mode

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[probot-home-assistant]

Hey there @rytilahti, @syssi, @starkillerOG, @bieniu, mind taking a look at this pull request as it has been labeled with an integration (xiaomi_miio) you are listed as a code owner for? Thanks!
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[emontnemery]

This should be the same behavior as without the PR.
I don't think it's really correct though; the light will be stuck in hs mode once a color is set.

Does the miio library offer any way to get the color mode for a PhilipsMoonlight?

[rytilahti]

The library does not provide that at the moment and I'm not sure if it can be derived from the data returned by the device. Maybe @syssi knows if that's even possible?

[emontnemery]

@rytilahti @syssi If the library offers no way to get the color mode I suggest to merge this PR, it should not result in any changed behavior

[frenck]

I think this is fine as an (intermediate) solution.