Fix old reference to TermApp::Command (microsoft#7863)

microsoft#7796 and microsoft#7667 were being implemented concurrently. As a part of microsoft#7667, Command was moved from TermApp to TSM. This just applies that change to a line we missed in microsoft#7796 and fixes the build break.

src/cascadia/TerminalApp/CommandPalette.cpp

@@ -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);