Restore isy light brightness after off

[bdraco]

Proposed change

ISY forget the brightness when turning on an off a light. I had assumed this was expected behavior but learned otherwise here (#34299 (comment))

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

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Additional information

• This PR fixes or closes issue: fixes #
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Checklist

• The code change is tested and works locally.
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[bdraco]

Before

After

[bdraco]

TYVM