Create auxHeatOnly switch in Ecobee integration

[bjpetit]

Proposed change

Add switch entity for ecobee auxHeatOnly behavior. This follows the
prior behavior of the deprecated aux_heat services and aux_heat toggle.

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)
• Deprecation (breaking change to happen in the future)
• 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:
• This PR is related to issue: ecobee - aux heater is deprecated #114026
• Link to documentation pull request: Update ecobee aux_heat details home-assistant.io#32502

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.
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• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

If the code communicates with devices, web services, or third-party tools:

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  Updated and included derived files by running: python3 -m script.hassfest.
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  Updated by running python3 -m script.gen_requirements_all.
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stale

[bjpetit]

Need to sync up with latest ecobee commit. Moving back to draft.

[bjpetit]

I've rebased and refactored this switch based on the newly introduced switch code in this integration.

[bjpetit]

I've updated this PR to focus on implementing the Aux Heat switch in the ecobee integration.
It appears that there is already code in the Climate component (See #112532) which should raise an issue for the deprecation of the aux_heat state.