Fix threading error in zha (#62170)

homeassistant/components/zha/core/discovery.py

@@ -234,6 +234,7 @@ class GroupProbe:
             unsub()
             self._unsubs.remove(unsub)
 
+    @callback
     def _reprobe_group(self, group_id: int) -> None:
         """Reprobe a group for entities after its members change."""
         zha_gateway = self._hass.data[zha_const.DATA_ZHA][zha_const.DATA_ZHA_GATEWAY]