(DOCSP-33812) Adds Atlas CTA for RS conversion to sharded page (#5168) (#5188)

Author: sarahsimpers

source/tutorial/convert-replica-set-to-replicated-shard-cluster.txt

@@ -19,6 +19,14 @@ replica set. This tutorial is specific to MongoDB {+latest-lts-version+}.
 For other versions of MongoDB, refer to the corresponding version of the
 MongoDB Manual.
 
+.. |page-topic| replace:: :atlas:`convert to a sharded cluster in the UI </scale-cluster/#convert-a-replica-set-to-a-sharded-cluster>`
+
+.. cta-banner::
+   :url: https://www.mongodb.com/docs/atlas/scale-cluster/#convert-a-replica-set-to-a-sharded-cluster
+   :icon: Cloud
+
+   .. include:: /includes/fact-atlas-compatible.rst
+
 The procedure is as follows:
 
 #. Create the initial three-member replica set and insert data into a