Fix(eos_config_deploy_cvp): avoid making CV_DEVICES becoming None (#1300

)

Co-authored-by: ClausHolbechArista <48674677+ClausHolbechArista@users.noreply.github.com>

ansible_collections/arista/avd/roles/eos_config_deploy_cvp/templates/cvp-devices-v3.j2

@@ -1,27 +1,29 @@
 {% set local_var = namespace() %}
 {% set local_var.device_filter = [] %}
 {% if device_filter is string %}
-{%    do local_var.device_filter.append(device_filter) %}
+{%     do local_var.device_filter.append(device_filter) %}
 {% else %}
-{%    set local_var.device_filter = device_filter %}
+{%     set local_var.device_filter = device_filter %}
 {% endif %}
+{% set dev_cntr = namespace(value=0) %}
 ---
 CVP_DEVICES:
 {% for device in groups[container_root] | arista.avd.natural_sort %}
 {%     if device | arista.avd.is_in_filter(local_var.device_filter) %}
 {%         if hostvars[device]['is_deployed'] is arista.avd.defined(true) or hostvars[device]['is_deployed'] is not arista.avd.defined %}
   - fqdn: {{ device }}
+{%             set dev_cntr.value = dev_cntr.value + 1 %}
 {%             for container_name, container in CVP_VARS.CVP_TOPOLOGY.items() | arista.avd.natural_sort %}
 {%                 if 'devices' in container %}
-{%                     for device_container in container['devices']%}
+{%                     for device_container in container['devices'] %}
 {%                         if device == device_container %}
     parentContainerName: {{ container_name }}
 {%                         endif %}
 {%                     endfor %}
 {%                 endif %}
 {%             endfor %}
     configlets:
-{%             if hostvars[groups[container_root][0]]['cv_configlets']['devices'][device] is defined %}
+{%             if hostvars[groups[container_root][0]]['cv_configlets']['devices'][device] is arista.avd.defined %}
 {%                 for configlet in hostvars[groups[container_root][0]]['cv_configlets']['devices'][device] | arista.avd.natural_sort %}
       - {{ configlet }}
 {%                 endfor %}
@@ -30,6 +32,9 @@ CVP_DEVICES:
 {%         endif %}
 {%     endif %}
 {% endfor %}
+{% if dev_cntr.value == 0 %}
+  []
+{% endif %}
 CVP_CONTAINERS:
 {% for container_name, container in CVP_VARS.CVP_TOPOLOGY.items() | arista.avd.natural_sort %}
   {{ container_name }}:
@@ -39,5 +44,5 @@ CVP_CONTAINERS:
 {%         for configlet in hostvars[groups[container_root][0]]['cv_configlets']['containers'][container_name] | arista.avd.natural_sort %}
       - {{ configlet }}
 {%         endfor %}
-{%      endif %}
-{% endfor %}
+{%     endif %}
+{% endfor %}