Description of problem:
undercloud-heat-purge-deleted validation is one of many pre-update validations.
It is run as a part of pre-update validations in osp17.0 and  it is failing with this error:

validation history get d8eb3132-4599-48bc-a03f-f63131fdd8a4
Validation config file found: /etc/validation.cfg
{
    "hosts": {
        "undercloud": {
            "_ansible_no_log": false,
            "action": "shell",
            "changed": false,
            "cmd": "set -o pipefail\npodman exec heat_api_cron crontab -l -u heat |grep -v '^#'\n",
            "delta": "0:00:00.072307",
            "end": "2022-07-08 11:46:47.863278",
            "failed": true,
            "invocation": {
                "module_args": {
                    "_raw_params": "set -o pipefail\npodman exec heat_api_cron crontab -l -u heat |grep -v '^#'\n",
                    "_uses_shell": true,
                    "argv": null,
                    "chdir": null,
                    "creates": null,
                    "executable": null,
                    "removes": null,
                    "stdin": null,
                    "stdin_add_newline": true,
                    "strip_empty_ends": true,
                    "warn": false
                }
            },
            "msg": "non-zero return code",
            "rc": 1,
            "start": "2022-07-08 11:46:47.790971",
            "stderr": "Error: no container with name or ID \"heat_api_cron\" found: no such container",
            "stderr_lines": [
                "Error: no container with name or ID \"heat_api_cron\" found: no such container"
            ],
            "stdout": "",
            "stdout_lines": []
        }
    },
    "name": "Get heat crontab",
    "status": "FAILED"
}

The validation verifies that heat-manage purge_deleted is enabled in crontab.
By default, starting from wallaby, we use ephemeral Heat and the heat_api_cron is not deployed on undercloud.
https://review.opendev.org/c/openstack/python-tripleoclient/+/796304 

Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
1.Deploy osp17.0 
2.Run 'validation run --group pre-update ' before starting update
3.

Actual results:
undercloud-heat-purge-deleted validation is being executed and is failing

Expected results:
Validations should be disabled from wallaby onwards or not executed when ephemeral Heat is used

Additional info: