container: fix ansible check mode when image not present on host

roles/container/tasks/image.yml

@@ -43,9 +43,10 @@
         name: "{{ ('local_' + docker_service) if dockerfile is defined and dockerfile | length > 0 else docker_image }}"
       register: existing_image
 
-    - name: Set check nmode container_image variable
+    - name: Set check mode container_image variable
       set_fact:
         container_image: "{{ existing_image.images[0] }}"
+      when: existing_image.images | length > 0
 
 - name: Set image user variable
   set_fact: