remove unused comment

Signed-off-by: fufesou <shuanglongchen@yeah.net>

src/plugin/callback_msg.rs

@@ -283,8 +283,6 @@ fn request_plugin_sign(id: String, msg_to_rustdesk: MsgToRustDesk) -> PluginRetu
     thread::spawn(move || {
         let sign_url = format!("{}/lic/web/api/plugin-sign", get_api_server());
         let client = reqwest::blocking::Client::new();
-        // to-do: Add peer id and plugin_id in the message to sign.
-        // So that the server can verify the ids.
         let req = PluginSignReq {
             peer_id: crate::ui_interface::get_id(),
             plugin_id: id.clone(),