Crash using script::Engine at exit to print console output (e.g. in Dialog close event)

[sentry-io]

Sentry Issue: ASEPRITE-7D

This crash happens when a Lua error happens in a Dialog onclose event handler (so the App::m_engine is nullptr and cannot be used to print the error).

EXC_BAD_ACCESS / KERN_INVALID_ADDRESS / 0x8: Fatal Error: EXC_BAD_ACCESS / KERN_INVALID_ADDRESS / 0x8
  File "../src/app/script/engine.cpp", line 567, in app::script::Engine::onConsolePrint
    if (m_delegate)
  File "../src/app/script/engine.h", line 98, in app::script::Engine::consolePrint
    onConsolePrint(text);
  File "../src/app/script/dialog_class.cpp", line 216, in app::script::(anonymous namespace)::Dialog_connect_signal<T>::lambda::operator()
    ->consolePrint(s);
  File "type_traits", line 3694, in std::__1::__invoke<T>
    _LIBCPP_INVOKE_RETURN(_VSTD::forward<_Fp>(__f)(_VSTD::forward<_Args>(__args)...))
  File "__functional_base", line 348, in std::__1::__invoke_void_return_wrapper<T>::__call<T>
    _VSTD::__invoke(_VSTD::forward<_Args>(__args)...);
...
(17 additional frame(s) were not displayed)