Remove use of stored state for service_ready

Remove saving service_ready in stored state in
OVNPebbleHandler class.

Change-Id: Ie42a6de078754998add15d23e01276cfa53d1079

ops-sunbeam/doc/howto-pebble-handler.rst

@@ -104,7 +104,6 @@ with the event can be overridden.
         self.execute(["run", "special", "command"])
         logger.debug(f"Plan: {container.get_plan()}")
         self.ready = True
-        self._state.pebble_ready = True
         self.charm.configure_charm(event)
 
 Configuring Charm to use custom pebble handler

ops-sunbeam/ops_sunbeam/ovn/container_handlers.py

@@ -49,7 +49,6 @@ class OVNPebbleHandler(sunbeam_chandlers.ServicePebbleHandler):
         """
         self.setup_dirs()
         self.write_config(context)
-        self._state.service_ready = True
         self.status.set(ActiveStatus(""))
 
     @property