Add proxy host into allow list (#20798)

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

services/migrations/migrate.go

@@ -479,5 +479,10 @@ func Init() error {
 	}
 	// TODO: at the moment, if ALLOW_LOCALNETWORKS=false, ALLOWED_DOMAINS=domain.com, and domain.com has IP 127.0.0.1, then it's still allowed.
 	// if we want to block such case, the private&loopback should be added to the blockList when ALLOW_LOCALNETWORKS=false
+
+	if setting.Proxy.Enabled && setting.Proxy.ProxyURLFixed != nil {
+		allowList.AppendPattern(setting.Proxy.ProxyURLFixed.Host)
+	}
+
 	return nil
 }