[Remote Store] Introduce validation of index template for restricted remote store backed indices

Is your feature request related to a problem? Please describe. Today, we allow index template creation and skip doing validation which can lead to issues when the index creation is happening though the index template. We need to introduce validation to ensure we do not allow creating such index templates that will ultimately fail to execute.

Describe the solution you'd like Validate index template creation.

Describe alternatives you've considered Validate combined template settings at the time of index creation.

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