[Remote Store] Validation while updating CompatibilityMode setting

[ltaragi]

Is your feature request related to a problem? Please describe

The following two checks should be implemented while updating the CompatibilityMode setting:

• Don't allow changing the CompatibilityMode (STRICT <--> MIXED) if all the nodes in the cluster are not of the same open search version
• Don't allow switching to STRICT mode if the cluster contains both remote and non-remote nodes

Describe the solution you'd like

This can be accomplished as follows:

• TransportClusterUpdateSettingsAction receives both the ClusterUpdateSettingsRequest and ClusterState objects
• The requested new value for CompatibilityMode can be found inside the ClusterUpdateSettingsRequest object
• Information on nodes like remote store enabled nature and opensearch version can be found inside the ClusterState object
• The above checks can be implemented with this available information

Related component

Storage:Remote

Describe alternatives you've considered

No response

Additional context

No response