### Description

https://github.com/apache/airflow/pull/17946 implements a `/robots.txt` endpoint to block search engines crawling Airflow - in the cases where it is (accidentally) exposed to the public Internet.

If we record any GET requests to that end-point we'd have a strong warning flag that the deployment is exposed, and could issue a warning in the UI, or even enable some kill-switch on the deployment. 

Some deployments are likely intentionally available and rely on auth mechanisms on the `login` endpoint, so there should be a config option to suppress the warnings.

An alternative approach would be to monitor for requests from specific user-agents used by crawlers for the same reasons

### Use case/motivation

People who accidentally expose airflow have a slightly higher chance of realising they've done so and tighten their security.

### Related issues

_No response_

### Are you willing to submit a PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

airflow/www/views.py
}
def task_group_to_dict(task_item_or_group):
    """
    Create a nested dict representation of this TaskGroup and its children used to construct
    the Graph.
    """
    if isinstance(task_item_or_group, BaseOperator):
        return {
            'id': task_item_or_group.task_id,
            'value': {
                'label': task_item_or_group.label,
                'labelStyle': f"fill:{task_item_or_group.ui_fgcolor};",
                'style': f"fill:{task_item_or_group.ui_color};",
                'rx': 5,
                'ry': 5,
            },
        }
    task_group = task_item_or_group
    children = [
        task_group_to_dict(child) for child in sorted(task_group.children.values(), key=lambda t: t.label)
    ]
    if task_group.upstream_group_ids or task_group.upstream_task_ids:
        children.append(
            {
                'id': task_group.upstream_join_id,
                'value': {
                    'label': '',
                    'labelStyle': f"fill:{task_group.ui_fgcolor};",
                    'style': f"fill:{task_group.ui_color};",
                    'shape': 'circle',