Fix incorrect comparison of speed "off" by identity instead of by value

[prystupa]

Proposed change

This fixes incorrect comparison of fan speed using "is" instead of "==". When turn_on service is called from UI, the speed variable is NOT reference-equal to SPEED_OFF constant, so speed is SPEED_OFF is False, and turn_off() branch of the logic is never executed as intended.

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 #
• This PR is related to issue:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
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