Do not attempt to check TLS state for dry-runs

[phooijenga]

When running helm template or passing --dry-run, the built-in lookup function always returns an empty map. This results in the check thinking that TLS is currently not enabled for RPCs, generating an error.

To reproduce:

$ helm install redpanda redpanda/redpanda
...
$ helm upgrade redpanda redpanda/redpanda --dry-run
Error: UPGRADE FAILED: execution error at (redpanda/templates/statefulset.yaml:60:28): 

Error: Cannot do a rolling restart to enable or disable tls at the RPC layer: changing listeners.rpc.tls.enabled (redpanda.yaml:repdanda.rpc_server_tls.enabled) from false to true
***WARNING The following instructions will result in a short period of downtime.
To accept this risk, run the upgrade again adding `--set force=true` and do the following:

While helm is upgrading the release, manually delete ALL the pods:
    kubectl -n infra delete pod -l app.kubernetes.io/component=redpanda-statefulset

If you got here thinking rpc tls was already enabled, see technical service bulletin 2023-01.

$ helm upgrade redpanda redpanda/redpanda
Release "redpanda" has been upgraded. Happy Helming!
...

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[phooijenga]

I noticed the lint action failed because the branch did not include a version bump, so I rebased and added one.