check if 'plugins' key exists in calico_cni_config object (#7717)

* check if 'plugins' key exists in calico_cni_config object

* fix whitespace linting error

* fixed when list indentation

roles/network_plugin/calico/tasks/pre.yml

@@ -12,7 +12,9 @@
   - name: Set fact calico_datastore to etcd if needed
     set_fact:
       calico_datastore: etcd
-    when: "'etcd_endpoints' in calico_cni_config.plugins.0"
+    when:
+    - "'plugins' in calico_cni_config"
+    - "'etcd_endpoints' in calico_cni_config.plugins.0"
   when: calico_cni_config_slurp.content is defined
 
 - name: Calico | Get kubelet hostname