[anti-censorship-alerts] [FIRING:1] Snowflake probetest failures

[Cecylia Bocovich]

> Total firing alerts: 1
> Total resolved alerts: 0
>
>
> ## Firing Alerts
>
> -----
> Time: 2022-01-29 18:59:00.286335746 +0000 UTC
> Summary:  There is a problem testing the type of NAT of our proxies
> Description:  There are only 2.0 times proxies with known NAT type than with unknown

I took a quick look at this and the problem isn't so apparent that I'm 
confident we've hit the issue we have in the past. I'll keep an eye on 
it for a few hours and follow the steps to produce debug information 
outlined here if it becomes more apparent we've hit the issue: 
https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/-/issues/40071#note_2770188

Cecylia