revert(iam): back out the SMTP values block that dropped the config ConfigMap

The sync removed zitadel-config-yaml while the Deployment still mounts it, so
the next pod restart would have failed. Restore the previous render first; the
relay stays deployed and can be wired once the chart accepts the block.

k8s/infra/iam/zitadel-values.yaml

@@ -31,23 +31,6 @@ zitadel:
     ExternalDomain: zitadel.riotpiao.com
     TLS:
       Enabled: false
-    # Notification delivery. ZITADEL speaks SMTP only, and this cluster has no
-    # mail path: without it every verification and password-reset message is
-    # dropped, so nobody can finish a first login. Point SMTP at the in-cluster
-    # smtp-gotify relay (k8s/infra/iam/smtp-gotify.yaml), which forwards each
-    # message to Gotify so codes arrive on the phone.
-    #
-    # TLS is false because the relay speaks plain SMTP inside the cluster and
-    # never leaves it. Host and credentials stay out of this file: no auth is
-    # needed, and the relay holds the Gotify token in the smtp-gotify Secret.
-    DefaultInstance:
-      SMTPConfiguration:
-        SMTP:
-          Host: smtp-gotify.iam.svc.cluster.local:2525
-        TLS: false
-        From: [email protected]
-        FromName: ZITADEL
-
     # First boot is COMPLETE (2026-10-26): the instance, the system org and the
     # `iam-admin` machine key all exist. Skip stops the setup hook from running
     # the first-instance step again. Without it, every sync re-runs the