fix: remove misleading 'control plane needs to have access to Internet' for the restricted environments (#2776)

Author: ibuziuk

modules/administration-guide/partials/snip_preparing-images-for-a-restricted-environment.adoc

@@ -7,7 +7,7 @@
 
 * The OpenShift cluster has at least 64 GB of disk space.
 
-* The OpenShift cluster is ready to operate on a restricted network, and the OpenShift control plane has access to the public internet. See link:https://docs.openshift.com/container-platform/{ocp4-ver}/installing/disconnected_install/index.html[About disconnected installation mirroring] and link:https://docs.openshift.com/container-platform/{ocp4-ver}/operators/admin/olm-restricted-networks.html[Using Operator Lifecycle Manager on restricted networks].
+* The OpenShift cluster is ready to operate on a restricted network. See link:https://docs.openshift.com/container-platform/{ocp4-ver}/installing/disconnected_install/index.html[About disconnected installation mirroring] and link:https://docs.openshift.com/container-platform/{ocp4-ver}/operators/admin/olm-restricted-networks.html[Using Operator Lifecycle Manager on restricted networks].
 
 // NOTE for testers: don't use the internal registry present on `crc`.