Fix module args for CI job, remove quotes from when clause

tests/integration/targets/rds_cluster/roles/rds_cluster/tasks/test_modify.yml

@@ -179,6 +179,7 @@
     rds_cluster:
       id: "{{ new_cluster_id }}"
       state: present
+      engine: "{{ engine }}"
       db_cluster_parameter_group_name: "{{ new_db_parameter_group_name }}"
       apply_immediately: True
     register: _result_modify_db_parameter_group_name