Remove unused instance variable in Z-wave (home-assistant#110442)

* Remove unused variable and fix typing in zwave_js

* remove redundant type

homeassistant/components/zwave_js/sensor.py

@@ -4,7 +4,7 @@
 from collections.abc import Callable, Mapping
 from dataclasses import dataclass
 from datetime import datetime
-from typing import Any, cast
+from typing import Any
 
 import voluptuous as vol
 from zwave_js_server.client import Client as ZwaveClient
@@ -19,7 +19,6 @@
 from zwave_js_server.model.driver import Driver
 from zwave_js_server.model.node import Node as ZwaveNode
 from zwave_js_server.model.node.statistics import NodeStatisticsDataType
-from zwave_js_server.model.value import ConfigurationValue
 from zwave_js_server.util.command_class.meter import get_meter_type
 
 from homeassistant.components.sensor import (
@@ -799,7 +798,6 @@ def __init__(
         super().__init__(
             config_entry, driver, info, entity_description, unit_of_measurement
         )
-        self._primary_value = cast(ConfigurationValue, self.info.primary_value)
 
         property_key_name = self.info.primary_value.property_key_name
         # Entity class attributes