ModalComponentManager safety improvement

[jimc]

static ModalComponentManager::Callback* create (std::function<void(int)>);

Would this be more useful (e.g. for showMenuAsync) if it took a Component as a WeakReference and then didn’t call the std::function if the WeakReference was no longer pointing anywhere useful?

[jules]

Yep, that’d certainly be a handy addition for that class!