Stuck on BlockedStatus even after maximum_retention_size config option changed to valid

[sed-i]

If we provide an invalid string to maximum_retention_size, the charm goes into BlockedStatus. Then, when it is corrected, there is no code in place to revert the status back to active.

prometheus-k8s-operator/src/charm.py

Lines 678 to 683 in c03298b

	try:
	ratio = self._percent_string_to_ratio(config.get("maximum_retention_size", ""))
	except ValueError as e:
	logger.warning(e)
	self.unit.status = BlockedStatus(f"Invalid retention size: {e}")