don't error when no client VMs exist

ansible/roles/win_client/tasks/chocolatey.yml

@@ -38,7 +38,7 @@
         bypass:
         - <local>
       when: |
-        inventory_hostname in groups['meta-type_client'] and
+        inventory_hostname in groups['meta-type_client']|default([]) and
         project_zone == 'protected'
 
     - name: Install Chocolatey GUI

ansible/roles/win_domain_membership/tasks/join.yml

@@ -40,4 +40,4 @@
         state: "domain"
         domain_ou_path: ou=Workbench,dc={{ win_project }},dc=loc
         reboot: true
-      when: "inventory_hostname in groups['meta-type_client']"
+      when: "inventory_hostname in groups['meta-type_client']|default([])"