Exclude the private mirrors from the mirrors list in the case of fallback behavior

[soksanichenko]

Change https://github.com/AlmaLinux/mirrors/blob/mirrors_service/src/backend/api/handlers.py#L187-L190 to make the call with without_private_mirrors=True

[PhirePhly]

To expand on the context here, I noted that when a client doesn't match on the network service cone (subnets and/or ASNs) of any mirrors, it falls back to rely on geo data to find near-by mirrors.

The get_mirrors_list()→ _get_nearest_mirrors(without_private_mirrors=False)→_get_nearest_mirrors_by_geo_data() call chain then fails to account for private mirrors only servicing their specified network cones.

The failure modes here are:

1. A client which fails geo match lookup receives a full list of mirrors, including private mirrors.
2. A private mirror accidentally incudes geo data in their mirror.d configuration file, and starts matching as an option for other near-by clients outside their network service cone.

[soksanichenko]

Result from dev machine

[ec2-user@ip-172-31-90-25 ~]$ curl -H "X-Forwarded-For: 127.0.0.1" http://localhost/mirrorlist/8/appstream 2>&1 | grep "centos.corp.cloudlinux.com"
[ec2-user@ip-172-31-90-25 ~]$

For 127.0.0.1 the service should return full list and centos.corp.cloudlinux.com is private mirror

[soksanichenko]

The patch is deployed to production