Scale-in operation fails on OpenStack Instance HA nodes with "'compute_instanceha_short_node_names' is undefined" error

Issue

• Scale-in operation fails on OpenStack Instance HA nodes with 'compute_instanceha_short_node_names' is undefined error on Getting Nova compute hostname task:

  $ openstack overcloud node delete ......
        :
  2025-01-01 12:49:51.511832 | aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa |      FATAL | Getting Nova compute hostname | instance-ha-compute-0 | error={"msg": "The conditional check 'inventory_hostname_short in compute_instanceha_short_node_names' failed. The error was: error while evaluating conditional (inventory_hostname_short in compute_instanceha_short_node_names): 'compute_instanceha_short_node_names' is undefined. 'compute_instanceha_short_node_names' is undefined\n\nThe error appears to be in '/home/stack/overcloud-deploy/overcloud/config-download/overcloud/scale_steps_tasks.yaml': line 47, column 5, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n  block:\n  - command: crm_node -n\n    ^ here\n"}