Remove invalid custom device class from MinutPoint sound sensor

[frenck]

Proposed change

This integration configured a device class sound_level on a sensor, but that is not a valid device class; It also isn't used for translations, thus should be removed.

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• Dependency upgrade
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• Breaking change (fix/feature causing existing functionality to break)
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• This PR fixes or closes issue: fixes #
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[home-assistant]

Hey there @fredrike, mind taking a look at this pull request as it has been labeled with an integration (point) you are listed as a code owner for? Thanks!

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[MartinHjelmare]

Should we label this a breaking change?

[frenck]

I estimate the impact on this one is basically nihil, as almost no usage is registered for this integration. Combining that with actual use of iterating states in templates for the use of this device class, would be extremely unlikely.

[MartinHjelmare]

Ok.