Use two separate methods for updating storage/distributor metrics

[daniil-berg]

Currently the Monitoring._update_metrics method handles both StorageStatus and DistributorStatus arguments and simply swallows AttributeErrors, assuming that metric labels and status object type match.

videbo/src/videbo/storage/monitoring.py

Lines 117 to 124 in e7b53e0

	def _update_metrics(self, status_obj: Union[StorageStatus, DistributorStatus], *labels: str) -> None:
	for name, (metric, get_value) in self.metrics.items():
	try:
	val = get_value(status_obj) if get_value else getattr(status_obj, name)
	except AttributeError:
	pass # some metrics apply exclusively to the storage node or a distributor, but not both
	else:
	metric.labels(*labels).set(val or 0)

This should be made more type safe/robust, by having distinct methods for storage vs. distributor metrics.