Add rpk cluster config command to Iceberg doc

Author: kbatuigas

modules/manage/partials/iceberg/use-iceberg-catalogs.adoc

@@ -11,7 +11,6 @@ For production deployments, Redpanda recommends using an external REST catalog t
 
 After you have selected a catalog type at the cluster level and xref:{about-iceberg-doc}#enable-iceberg-integration[enabled the Iceberg integration] for a topic, you cannot switch to another catalog type.
 
-//ifndef::env-cloud[]
 == Connect to a REST catalog
 
 Connect to an Iceberg REST catalog using the standard https://github.com/apache/iceberg/blob/main/open-api/rest-catalog-open-api.yaml[REST API^] supported by many catalog providers. Use this catalog integration type with REST-enabled Iceberg catalog services, such as https://docs.databricks.com/en/data-governance/unity-catalog/index.html[Databricks Unity^] and https://other-docs.snowflake.com/en/opencatalog/overview[Snowflake Open Catalog^].
@@ -103,7 +102,7 @@ rpk::
 --
 [,bash]
 ----
-rpk
+rpk cluster config set iceberg_rest_catalog_client_secret <secret-name>
 ----
 --
 
@@ -174,8 +173,10 @@ SELECT * FROM streaming.redpanda.<table-name>;
 
 The Iceberg table name is the name of your Redpanda topic. Redpanda puts the Iceberg table into a namespace called `redpanda`, creating the namespace if necessary. 
 
+// Hide section in Cloud until Snowflake doc is single sourced
+ifndef::env-cloud[]
 TIP: You may need to explicitly create a table for the Iceberg data in your query engine. For an example, see xref:manage:iceberg/redpanda-topics-iceberg-snowflake-catalog.adoc[].
-
+endif::[]
 
 == Integrate filesystem-based catalog (`object_storage`)