fix some netplay state (#1046)

src/ui/gui/appwindow.slint

@@ -378,6 +378,9 @@ export component AppWindow inherits Window {
         NetplayData.password = "";
         NetplayData.session_name = "";
         NetplayWaitData.chat_text = "";
+        NetplayWaitData.input_delay = 0;
+        NetplayWaitData.recommended_delay = 0;
+        NetplayWaitData.players = [];
         NetplayData.pending_session = false;
         NetplayData.pending_refresh = false;
     }

src/ui/netplay.rs

@@ -352,7 +352,11 @@ fn join_session(
     password: String,
 ) {
     let session = NetplaySession {
-        password: Some(password),
+        password: if password.is_empty() {
+            None
+        } else {
+            Some(password)
+        },
         game_name: None,
         motd: None,
         game_checksum: Some(game_hash),