IPv4 routing issue between Prometheus servers (Hetzner NBG1) and Dallas cluster

@lelutin fild the following with Hetzner:

Subject: [Ticket#2024082903021681] RE: General
[...]
> IPv4 Routing between our hosts at Hetzner and all IPs in another site in Dallas, at
> Quintex, are currently not working. The IPs that are unreachable are 204.8.96.0/22
> 
> In a traceroute, we seem to be able to reach other routers in hetzner, but responses
> stop in Paris:
> 
> # traceroute -4 ssh-dal-01.torproject.org
> traceroute to ssh-dal-01.torproject.org (204.8.99.153), 30 hops max, 60 byte packets
>  1  172.31.1.1 (172.31.1.1)  10.298 ms  10.310 ms  10.270 ms
>  2  11812.your-cloud.host (195.201.67.252)  1.423 ms  1.522 ms  1.457 ms
>  3  * * *
>  4  spine7.cloud1.nbg1.hetzner.com (85.10.230.57)  46.555 ms  46.491 ms  46.416 ms
>  5  * * *
>  6  core12.nbg1.hetzner.com (213.239.203.105)  0.780 ms  0.371 ms
> core12.nbg1.hetzner.com (213.239.239.141)  0.378 ms
>  7  core6.par.hetzner.com (213.239.237.238)  13.098 ms core6.par.hetzner.com
> (213.239.237.242)  12.918 ms  12.819 ms
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