Fix KNX Light: turn_on with brightness and color_temperature

[farmio]

Proposed change

Process both brightness and color_temperature in a turn_on call.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes KNX light can't update both brightness and color temperature in the same call #30299
• This PR is related to issue:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• The code has been formatted using Black (black --fast homeassistant tests)
• Tests have been added to verify that the new code works.

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  Updated and included derived files by running: python3 -m script.hassfest.
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[probot-home-assistant]

Hey there @Julius2342, mind taking a look at this pull request as its been labeled with a integration (knx) you are listed as a codeowner for? Thanks!

[farmio]

The failed test is not related to this PR.

[balloob]

So now you will go down multiple paths and have conflicting changes?

[farmio]

I think the source of the conflicting changes was sending an ON telegram after eg. brightness so the actuators default turn-on-value overwrote the brightness telegram.

We only send an ON telegram if no other light option is updated. (Line 273).

Only problem I could imagine is actuator specific. Some don't turn on when receiving a color-temperature telegram only. They expect either ON or brightness. But I think HA ui doesn't allow to set color-temperature on a turned off light.