Fix double percent encoding of invites

src/ChatPage.cpp

@@ -1015,8 +1015,7 @@ ChatPage::trySync()
 void
 ChatPage::joinRoom(const QString &room)
 {
-        // Percent escape the room ID
-        const auto room_id = QUrl::toPercentEncoding(room).toStdString();
+        const auto room_id = room.toStdString();
 
         http::client()->join_room(
           room_id, [this, room_id](const nlohmann::json &, mtx::http::RequestErr err) {