LibWebView+RequestServer: Add some UI for DNS settings

Author: https://github.com/alimpfard
Commit: 2c13504bfc
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/4278
Reviewed-by: https://github.com/trflynn89 ✅

Services/RequestServer/RequestServer.ipc

@@ -10,6 +10,7 @@ endpoint RequestServer
 
     // use_tls: enable DNS over TLS
     set_dns_server(ByteString host_or_address, u16 port, bool use_tls) =|
+    set_use_system_dns() =|
 
     // Test if a specific protocol is supported, e.g "http"
     is_supported_protocol(ByteString protocol) => (bool supported)