### Godot version

v4.2.rc.custom_build [702227129]

### System information

Godot v4.2.rc (702227129) - Debian GNU/Linux trixie/sid trixie - X11 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1060 6GB (nvidia) - AMD Ryzen 5 1600 Six-Core Processor (12 Threads)

### Issue description

Found a consistent crash when calling `hide()` from `_notification()`.
It does not happen if the call is deferred.

### Steps to reproduce

The `hide_test.gd` script has a boolean `cause_crash`. If it is true, hovering the mouse over the label crashes without an error in the Godot Editor Console. If it's false it hides the label as expected.

### Minimal reproduction project

[hide_crash.zip](https://github.com/godotengine/godot/files/13452818/hide_crash.zip)

Window *old_focus = gui.subwindow_focused;
	gui.subwindow_focused = p_window;
	gui.subwindow_focused->_event_callback(DisplayServer::WINDOW_EVENT_FOCUS_IN);
	{ 
		index = _sub_window_find(p_window);
		ERR_FAIL_COND(index == -1);
		SubWindow sw = gui.sub_windows[index];
		gui.sub_windows.remove_at(index);
		gui.sub_windows.push_back(sw);
		index = gui.sub_windows.size() - 1;
		_sub_window_update_order();
	}
	if (old_focus) {
		_sub_window_update(old_focus);
	}
	_sub_window_update(p_window);
}
void Viewport::_sub_window_remove(Window *p_window) {
	int index = _sub_window_find(p_window);
	ERR_FAIL_COND(index == -1);
	ERR_FAIL_NULL(RenderingServer::get_singleton());
	SubWindow sw = gui.sub_windows[index];
	if (gui.subwindow_over == sw.window) {
		sw.window->_mouse_leave_viewport();
		gui.subwindow_over = nullptr;
	}
	RS::get_singleton()->free(sw.canvas_item);
	gui.sub_windows.remove_at(index);
	if (gui.sub_windows.size() == 0) {
		RS::get_singleton()->free(subwindow_canvas);