Remove default unit of measurement in IHC sensors

[dingusdk]

Breaking change

This PR will remove the default unit of measurement for manually set up sensors from ihc.
Home assistant now assume all sensors with unit of measurement set is a number.
Ihc sensors can be text, but because of the default unit of measurement, there is currently no way to get text sensors from ihc working.

This is a breaking fix, because if you currently have temperature sensors without unit of measurement set, you will have to set this for the sensors.

Proposed change

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: fixes #
• 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.
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• The code has been formatted using Black (black --fast homeassistant tests)
• 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

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[epenet]

LGTM 👍