### Godot version

4.1.dev 2e273f0e35800f2bcc7c05db54100caa97928f69

### System information

macOS 13.4

### Issue description

Removing a SpinBox from the node tree using `remove_child` during the line edit text submit signal will crash the engine.

```
handle_crash: Program crashed with signal 11
Engine version: Godot Engine v4.1.dev.custom_build (2e273f0e35800f2bcc7c05db54100caa97928f69)
Dumping the backtrace. Please include this when reporting the bug to the project developer.
[1] 1   libsystem_platform.dylib            0x0000000183b5aa24 _sigtramp + 56
[2] Viewport::gui_get_focus_owner() (in godot.macos.editor.arm64) + 32
[3] SpinBox::_line_edit_focus_exit() (in godot.macos.editor.arm64) + 28
[4] CallQueue::_call_function(Callable const&, Variant const*, int, bool) (in godot.macos.editor.arm64) + 336
[5] CallQueue::flush() (in godot.macos.editor.arm64) + 908
[6] SceneTree::physics_process(double) (in godot.macos.editor.arm64) + 244
[7] Main::iteration() (in godot.macos.editor.arm64) + 528
```

### Steps to reproduce

Open the minimal reproduction project, click on the SpinBox, press enter, and the engine crashes.

### Minimal reproduction project

[SpinBoxTextSubmitCrash.zip](https://github.com/godotengine/godot/files/11631081/SpinBoxTextSubmitCrash.zip)

if (p_node != this) {
		Window *w = Object::cast_to<Window>(p_node);
		if (w && (!w->is_inside_tree() || !w->is_embedded())) {
			return;
		}
		CanvasItem *ci = Object::cast_to<CanvasItem>(p_node);
		if (ci) {
			ci->queue_redraw();
		}
	}
	int cc = p_node->get_child_count();
	for (int i = 0; i < cc; i++) {
		_update_canvas_items(p_node->get_child(i));
	}
}
Ref<ViewportTexture> Viewport::get_texture() const {
	ERR_READ_THREAD_GUARD_V(Ref<ViewportTexture>());
	return default_texture;
}
void Viewport::set_positional_shadow_atlas_size(int p_size) {
	ERR_MAIN_THREAD_GUARD;
	positional_shadow_atlas_size = p_size;
	RS::get_singleton()->viewport_set_positional_shadow_atlas_size(viewport, p_size, positional_shadow_atlas_16_bits);
}
int Viewport::get_positional_shadow_atlas_size() const {