### Godot version

4.2 eb4301b

### System information

Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1060 (NVIDIA; 30.0.15.1403) - Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz (8 Threads)

### Issue description

Sometimes when trying to open a scene from filesystem dock, the editor will crash. It happened 3 times to me already, but I don't know what exactly causes it.
```
[0] FileSystemDock::_select_file (C:\godot_source\editor\filesystem_dock.cpp:1115)
[1] FileSystemDock::_select_file (C:\godot_source\editor\filesystem_dock.cpp:1115)
[2] FileSystemDock::_tree_activate_file (C:\godot_source\editor\filesystem_dock.cpp:1187)
[3] call_with_variant_args_helper<FileSystemDock> (C:\godot_source\core\variant\binder_common.h:308)
[4] call_with_variant_args<FileSystemDock> (C:\godot_source\core\variant\binder_common.h:418)
[5] CallableCustomMethodPointer<FileSystemDock>::call (C:\godot_source\core\object\callable_method_pointer.h:105)
[6] Callable::callp (C:\godot_source\core\variant\callable.cpp:51)
[7] Object::emit_signalp (C:\godot_source\core\object\object.cpp:1073)
[8] Node::emit_signalp (C:\godot_source\scene\main\node.cpp:3577)
[9] Object::emit_signal<> (C:\godot_source\core\object\object.h:891)
[10] Tree::gui_input (C:\godot_source\scene\gui\tree.cpp:3867)
[11] Control::_call_gui_input (C:\godot_source\scene\gui\control.cpp:1806)
[12] Viewport::_gui_call_input (C:\godot_source\scene\main\viewport.cpp:1565)
[13] Viewport::_gui_input_event (C:\godot_source\scene\main\viewport.cpp:1794)
[14] Viewport::push_input (C:\godot_source\scene\main\viewport.cpp:3129)
[15] Window::_window_input (C:\godot_source\scene\main\window.cpp:1482)
[16] call_with_variant_args_helper<Window,Ref<InputEvent> const &,0> (C:\godot_source\core\variant\binder_common.h:303)
[17] call_with_variant_args<Window,Ref<InputEvent> const &> (C:\godot_source\core\variant\binder_common.h:418)
[18] CallableCustomMethodPointer<Window,Ref<InputEvent> const &>::call (C:\godot_source\core\object\callable_method_pointer.h:105)
[19] Callable::callp (C:\godot_source\core\variant\callable.cpp:51)
[20] DisplayServerWindows::_dispatch_input_event (C:\godot_source\platform\windows\display_server_windows.cpp:2612)
[21] DisplayServerWindows::_dispatch_input_events (C:\godot_source\platform\windows\display_server_windows.cpp:2577)
[22] Input::_parse_input_event_impl (C:\godot_source\core\input\input.cpp:722)
[23] Input::flush_buffered_events (C:\godot_source\core\input\input.cpp:979)
[24] DisplayServerWindows::process_events (C:\godot_source\platform\windows\display_server_windows.cpp:2296)
[25] OS_Windows::run (C:\godot_source\platform\windows\os_windows.cpp:1479)
[26] widechar_main (C:\godot_source\platform\windows\godot_windows.cpp:182)
[27] _main (C:\godot_source\platform\windows\godot_windows.cpp:204)
[28] main (C:\godot_source\platform\windows\godot_windows.cpp:218)
[29] WinMain (C:\godot_source\platform\windows\godot_windows.cpp:232)
[30] __scrt_common_main_seh (D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288)
[31] <couldn't map PC to fn name>
```

### Steps to reproduce

1. Open a project
2. Open a scene

I think the scene needs to be opened early enough.

### Minimal reproduction project

N/A
if (p_idx == 0) { 
		current_menu_option = FILE_EXPORT_MESH_LIBRARY;
		if (!editor_data.get_edited_scene_root()) {
			show_accept(TTR("This operation can't be done without a scene."), TTR("OK"));
			return;
		}
		List<String> extensions;
		Ref<MeshLibrary> ml(memnew(MeshLibrary));
		ResourceSaver::get_recognized_extensions(ml, &extensions);
		file_export_lib->clear_filters();
		for (const String &E : extensions) {
			file_export_lib->add_filter("*." + E);
		}
		file_export_lib->popup_file_dialog();
		file_export_lib->set_title(TTR("Export Mesh Library"));
	} else { 
		if (export_as_menu->get_item_submenu(p_idx).is_empty()) { 
			Callable callback = export_as_menu->get_item_metadata(p_idx);
			Callable::CallError ce;
			Variant result;
			callback.callp(nullptr, 0, result, ce);
			if (ce.error != Callable::CallError::CALL_OK) {
				String err = Variant::get_callable_error_text(callback, nullptr, 0, ce);
				ERR_PRINT("Error calling function from export_as menu: " + err);
			}
		}
	}
}
int EditorNode::_next_unsaved_scene(bool p_valid_filename, int p_start) {