CI: Revert to ens3 interface for Leafcloud

Leafcloud is not using the q35 machine type yet.

Author: markgoddard

.github/workflows/stackhpc-all-in-one.yml

@@ -34,7 +34,7 @@ on:
       vm_interface:
         description: Default network interface name
         type: string
-        default: enp3s0
+        default: ens3
       vm_flavor:
         description: Flavor for the all-in-one VM
         type: string