Merge pull request #60738 from skopacz1/OCPBUGS-14365

OCPBUGS#14365: clarifying platform support for agent

Author: gaurav-nelson

modules/understanding-agent-install.adoc

@@ -60,6 +60,11 @@ Recommended cluster resources for the following topologies:
 
 The following platforms are supported:
 
-* `none`
 * `baremetal`
 * `vsphere`
+* `none`
++
+[NOTE]
+====
+The `none` option is supported for only single-node OpenShift clusters with an `OVNKubernetes` network type.
+====