Fix unit inference for ITEMP field for APCUPSD integration

[yuxincs]

Proposed change

APCUPSd weirdly adds a trailing "Internal" for internal temperature ITEMP field (e.g., "30.5 C Internal" instead of "30.5 C"), which broke our simple unit inference / conversion algorithm in the integration. This PR adds unit inference support for ITEMP field reported from APCUPSd by adding a fake unit "C Internal" in the unit conversion dict.

Tests are also expanded to include such cases to prevent future regressions.

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 apcupsd: multiple sensors no longer reporting data #93132
• This PR is related to issue: apcupsd: multiple sensors no longer reporting data #93132
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
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• Tests have been added to verify that the new code works.

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[frenck]

Thanks, @yuxincs 👍

../Frenck