自定义 DNS 实际上不会更新系统 DNS

Is it a bug? - [x] I know this is an issue with the app, and contacting Mullvad support is not relevant. ### I have checked if others have reported this already - [x] I have checked the issue tracker to see if others have reported similar issues. ### Current Behavior Setting Mullvad custom DNS doesn't set the specified one in /etc/resolv.conf ### Expected Behavior Setting Mullvad custom DNS updates /etc/resolv.conf accordingly. ### Steps to Reproduce 1. Run mullvad dns set default 2. Run cat /etc/resolv.conf * nameserver 10.64.0.1 * Great. This seems to be working. 3. Run mullvad dns set custom 192.168.0.44 2. Run cat /etc/resolv.conf * nameserver 192.168.0.2 <- this is an old, now decommissioned DNS server * nameserver 9.9.9.9 <- don't know where this is coming from ### Failure Logs ```shell sep 13 18:06:42 Pengling mullvad-daemon[856]: DEBUG mullvad_daemon::management_interface: set_dns_options(DnsOptions { state: Default, default_options: DefaultDnsOptions { block_ads: false, block_trackers: false, block_malware: false, block_adult_content: false, block_gambling: false, block_social_media: false }, custom_options: CustomDnsOptions { addresses: [192.168.0.44] } }) sep 13 18:07:42 Pengling mullvad-daemon[856]: DEBUG mullvad_daemon::management_interface: get_settings sep 13 18:07:42 Pengling mullvad-daemon[856]: DEBUG mullvad_daemon::management_interface: set_dns_options(DnsOptions { state: Custom, default_options: DefaultDnsOptions { block_ads: false, block_trackers: false, block_malware: false, block_adult_content: false, block_gambling: false, block_social_media: false }, custom_options: CustomDnsOptions { addresses: [192.168.0.44] } }) sep 13 18:07:42 Pengling mullvad-daemon[856]: DEBUG mullvad_daemon::settings: Writing settings to /etc/mullvad-vpn/settings.json sep 13 18:07:42 Pengling mullvad-daemon[856]: DEBUG mullvad_daemon::management_interface: Broadcasting new settings sep 13 18:07:42 Pengling mullvad-daemon[856]: INFO talpid_core::firewall: Applying firewall policy: Connected to { 45.129.56.67:5825/UDP } over "wg0-mullvad" (ip: 10.147.105.181, v4 gw: 10.64.0.1, v6 gw: None), Allowing LAN sep 13 18:07:42 Pengling mullvad-daemon[856]: INFO talpid_dns: Setting DNS servers: Tunnel DNS: {} Non-tunnel DNS: {192.168.0.44} sep 13 18:07:42 Pengling mullvad-daemon[856]: DEBUG talpid_dns::imp: Can't manage DNS using systemd-resolved: systemd-resolved operation failed sep 13 18:07:42 Pengling mullvad-daemon[856]: DEBUG talpid_dbus::network_manager: /etc/resolv.conf differs from reference resolv.conf, therefore NM is not managing DNS sep 13 18:07:42 Pengling mullvad-daemon[856]: DEBUG talpid_dns::imp: Can't manage DNS using NetworkManager: NetworkManager is not managing DNS sep 13 18:07:42 Pengling mullvad-daemon[856]: DEBUG talpid_dns::imp: Can't manage DNS using resolveconf: The resolvconf in PATH is just a symlink to systemd-resolved