keycloak_client: fix ansible diff/changed (sorting, null-values) (#39515)

* - Fix sorting bug related to diff (attributes is sorted in the API, other lists are not)
- Remove null-valued entries from protocolMappers introduced by Ansible's argument spec checking (also fixes diff output).

* python2.6-ified dict comprehension

* avoid use of map

lib/ansible/modules/identity/keycloak/keycloak_client.py

@@ -741,13 +741,20 @@ def main():
     changeset = dict()
 
     for client_param in client_params:
-        # lists in the Keycloak API are sorted
         new_param_value = module.params.get(client_param)
+
+        # some lists in the Keycloak API are sorted, some are not.
         if isinstance(new_param_value, list):
+            if client_param in ['attributes']:
                 try:
                     new_param_value = sorted(new_param_value)
                 except TypeError:
                     pass
+        # Unfortunately, the ansible argument spec checker introduces variables with null values when
+        # they are not specified
+        if client_param == 'protocol_mappers':
+            new_param_value = [dict((k, v) for k, v in x.items() if x[k] is not None) for x in new_param_value]
+
         changeset[camel(client_param)] = new_param_value
 
     # Whether creating or updating a client, take the before-state and merge the changeset into it