Port opensearch lock fixes to rollingops

[carlcsaposs-canonical]

Fix for #11 (rollingops breaks with deferred events [if code that uses lock can defer]) available in opensearch here: https://github.com/canonical/opensearch-operator/blob/90444e320a4eb84f313a740ebc695d497db150ab/lib/charms/opensearch/v0/opensearch_locking.py#L30-L179

[github-actions]

https://warthogs.atlassian.net/browse/DPE-4181

[phvalguima]

I expect, for any path we take with rolling ops, to be able to handle scenarios in #22.