feat(manifest.json): change iot_class to calculated

[helto4real]

Proposed change

The iot_class in the manifest.json file has been changed from "cloud_polling" to "calculated". This change is to better reflect the nature of the IoT device's communication method.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (which adds functionalit)
• 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.
• There is no commented out code in this PR.
• The code has been formatted using Black (make black)
• Tests have been added to verify that the new code works.