### 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
"""Returns appropriate permission name depending on request method name."""
        if request:
            action_name = request.view_args.get("name")
            _, method_name = request.url_rule.endpoint.rsplit(".", 1)
            if method_name == 'action' and action_name:
                return self.class_permission_name_mapping.get(action_name, self._class_permission_name)
            if method_name:
                return self.class_permission_name_mapping.get(method_name, self._class_permission_name)
        return self._class_permission_name
    @class_permission_name.setter
    def class_permission_name(self, name):
        self._class_permission_name = name
    @expose("/show/<pk>", methods=["GET"])
    @has_access
    def show(self, pk):
        pk = self._deserialize_pk_if_composite(pk)
        widgets = self._show(pk)
        widgets['show'].template_args['actions'].pop('userinfoedit')
        return self.render_template(
            self.show_template,
            pk=pk,
            title=self.show_title,
            widgets=widgets,
            related_views=self._related_views,
        )
class CustomUserDBModelView(MultiResourceUserMixin, UserDBModelView):