Fix sync call in async context generic_thermostat (#34822)

homeassistant/components/generic_thermostat/climate.py

@@ -325,7 +325,7 @@ class GenericThermostat(ClimateEntity, RestoreEntity):
             _LOGGER.error("Unrecognized hvac mode: %s", hvac_mode)
             return
         # Ensure we update the current operation after changing the mode
-        self.schedule_update_ha_state()
+        self.async_write_ha_state()
 
     async def async_set_temperature(self, **kwargs):
         """Set new target temperature."""