Validate config when using Salt directly

The `ceph-salt deploy` command validates the configuration before starting the deployment, but those validations should also be executed if the user applies the state directly from Salt, e.g.: `salt -G 'ceph-salt:member' state.apply ceph-salt`

Start by tracing the validation flow used by `ceph-salt deploy` and the Salt `state.apply ceph-salt` entry point shown in the issue. Ensure the same configuration validations run for direct Salt application, then verify both invocation paths behave consistently with the project’s relevant tests.

Written by the indexing model from the issue text.