Reduce User Action Needed event spam

[Outshynd]

Simple change to make User Action Needed event fire once per minute.

Without this change, I would get rate-limited in Discord because 40 or 50 notifications were sent before I could get upstairs and swap filament. It was even worse if I didn't notice the notification right away, a whole channel with nothing but 'User action needed' messages, drowning out all else.

[derekantrican]

Thanks for your PR! I'm the new maintainer and I'm going to do a similar thing (I've tracked it here: This is now being tracked in the new repo here: https://github.com/derekantrican/OctoPrint-Webhooks/issues/5)