New BMW sensor for climate activity (#110287)

* add sensor with climate activity status

* Update strings.json

* use icon translation and is_available for sensor

* use enum with translations

* Return None if value is UNKNOWN

* fix getting the value: x.value

* fix getting the value: x instead of x.value

* Fix tests and pre-commit

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Co-authored-by: Richard <rikroe@users.noreply.github.com>