Merge pull request #66592 from obrown1205/oc-mirror_RSWarning

[OSDOCS#7874]: Added warning regarding oc-mirror for Operators vs clusters (release-signatures)

Author: jeana-redhat

modules/oc-mirror-updating-cluster-manifests.adoc

@@ -27,12 +27,17 @@ The `ImageContentSourcePolicy` resource associates the mirror registry with the
 $ oc apply -f ./oc-mirror-workspace/results-1639608409/
 ----
 
-. Apply the release image signatures to the cluster by running the following command:
+. If you mirrored release images, apply the release image signatures to the cluster by running the following command:
 +
 [source,terminal]
 ----
 $ oc apply -f ./oc-mirror-workspace/results-1639608409/release-signatures/
 ----
++
+[NOTE]
+====
+If you are mirroring Operators instead of clusters, you do not need to run `$ oc apply -f ./oc-mirror-workspace/results-1639608409/release-signatures/`. Running that command will return an error, as there are no release image signatures to apply.
+====
 
 // TODO: Any example output to show?