Setting automatic updates to run on cron and having cron run by drush makes automatic updates not run

Problem/Motivation

It's not that clear in the UI that is you select the Automated Cron module or a request to /system/cron that automatic updates will not run if cron is triggered by drush from a crontab. Also this limitation feels bizarre. Why does this option care whether it's from cron on the CLI or cron in a web browser?

Steps to reproduce

Proposed resolution

At the very least if the method is 'web' and we are on cronning via the command line we should put an error in the log so a user knows that automatic updates are no running on their site. But I think we should also have a comment in the code as to why we can't run from cron if cron is running from the command line - it seems an odd limitation.

Remaining tasks

User interface changes

API changes

Data model changes