message: Remove redundant file exists check when loading saved games
  The `Filesystem::open` code will already throw a clear exception if it
  fails to open a file.
diff: @@ -160,12 +160,6 @@ void MainMenuState::fileIoAction(const std::string& filePath, FileIo::FileOperat
  std::string filename = constants::SAVE_GAME_PATH + filePath + ".xml";
  - if (!Utility<Filesystem>::get().exists(filename))
  - {
  - doNonFatalErrorMessage("Load Failed", "File '" + filename + "' was not found.");
  - return;
  - }
  -
  try
  {
  checkSavegameVersion(filename);
  