Refactor ClusterGroup to streamline cluster creation process

- Updated the `create_or_update` method in the ClusterGroup class to set the `key` property to null and include the clusters in the new data object. This change enhances the clarity of the data being processed during cluster group creation or update, ensuring that unnecessary properties are omitted while maintaining essential information.

smart-cluster-groups/cluster_group.js

@@ -113,7 +113,8 @@ export class ClusterGroup extends CollectionItem {
         acc[key] = value;
         return acc;
       }, new_clusters);
-    const new_group = await this.env.cluster_groups.create_or_update({ ...this.data, clusters });
+    const new_data = { ...this.data, key: null, clusters };
+    const new_group = await this.env.cluster_groups.create_or_update(new_data);
     return new_group;
   }