Feat: OPENVPN_TARGET_IP overrides IP

- Check target IP matches a server for Wireguard since we need the public key
- Streamline connection picking for all providers

internal/provider/protonvpn/connection.go

@@ -34,9 +34,5 @@ func (p *Protonvpn) GetConnection(selection configuration.ServerSelection) (
 		}
 	}
 
-	if selection.TargetIP != nil {
-		return utils.GetTargetIPConnection(connections, selection.TargetIP)
-	}
-
-	return utils.PickRandomConnection(connections, p.randSource), nil
+	return utils.PickConnection(connections, selection, p.randSource)
 }