message: Fix old reference to TermApp::Command
  and were being implemented concurrently. As a part of Command was moved from TermApp to TSM. This just applies that change to a line we missed in and fixes the build break.
diff: @@ -132,7 +132,7 @@ namespace winrt::TerminalApp::implementation
  if (_currentMode == CommandPaletteMode::TabSwitchMode)
  {
  const auto& selectedCommand = _filteredActionsView().SelectedItem();
  - if (const auto& command = selectedCommand.try_as<TerminalApp::Command>())
  + if (const auto& command = selectedCommand.try_as<Command>())
  {
  const auto& actionAndArgs = command.Action();
  _dispatch.DoAction(actionAndArgs);
  