Crash deleting IntEntry popup when the slider is a child of the popup

[sentry-io]

Sentry Issue: ASEPRITE-1EN

Thread 188638 Crashed:
0   libsystem_kernel.dylib          0x7ff80d968ffe      __pthread_kill
1   libsystem_pthread.dylib         0x7ff80d99f1fe      pthread_kill
2   libsystem_c.dylib               0x7ff80d8ead23      abort
3   libsystem_malloc.dylib          0x7ff80d7c8356      malloc_vreport
4   libsystem_malloc.dylib          0x7ff80d7cb52a      malloc_report
5   aseprite                        0x10f2817f2         ui::Widget::~Widget (widget.cpp:84)
6   aseprite                        0x10f27740d         [inlined] ui::TransparentPopupWindow::~TransparentPopupWindow (popup_window.h:65)
7   aseprite                        0x10f27740d         [inlined] ui::TransparentPopupWindow::~TransparentPopupWindow (popup_window.h:65)
8   aseprite                        0x10f27740d         ui::TransparentPopupWindow::~TransparentPopupWindow (popup_window.h:65)
9   aseprite                        0x10f265d96         [inlined] std::__1::default_delete<T>::operator()[abi:v15006] (unique_ptr.h:48)
10  aseprite                        0x10f265d96         [inlined] std::__1::unique_ptr<T>::reset[abi:v15006] (unique_ptr.h:305)
11  aseprite                        0x10f265d96         [inlined] std::__1::unique_ptr<T>::operator=[abi:v15006]<T> (unique_ptr.h:236)
12  aseprite                        0x10f265d96         ui::IntEntry::openPopup (int_entry.cpp:180)
13  aseprite                        0x10f265af3         ui::IntEntry::onProcessMessage (int_entry.cpp:86)
14  aseprite                        0x10f26b9df         ui::Manager::pumpQueue (manager.cpp:1897)
15  aseprite                        0x10f26933d         ui::Manager::dispatchMessages (manager.cpp:864)
16  aseprite                        0x10f2694c7         ui::Manager::run (manager.cpp:292)
17  aseprite                        0x10eec4d30         app::App::run (app.cpp:546)
18  aseprite                        0x10eec2b12         app_main (main.cpp:148)
19  aseprite                        0x10f28c0b7         main (main.cpp:67)
20  dyld                            0x11279a52e         <unknown>
21  dyld                            0x11279a593         <unknown>
22  dyld                            0x11279a5ed         <unknown>
23  dyld                            0x11279a577         <unknown>
24  dyld                            0x11279a585         <unknown>