[FEATURE] Create Transport API for clusterService required for creating AD detector

[owaiskazi19]

Is your feature request related to a problem?

IndexAnomalyDetectorTransportAction requiresaddSettingsUpdateConsumer from clusterService.getClusterSettings() that adds a settings consumer that accepts the values for two settings.

What solution would you like?

A clear and concise description of what you want to happen.

What alternatives have you considered?

A clear and concise description of any alternative solutions or features you've considered.

Do you have any additional context?

Add any other context or screenshots about the feature request here.

[owaiskazi19]

For the initial phase of creating the detector as we are not taking Security in place. Keeping the work on hold and the initial draft PR for OpenSearch is here and for SDK is here.
We can continue this issue once we start integrating security with AD extension.

[owaiskazi19]

We have the support now for addSettingsUpdateConsumer now. Closing this issue.