### 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)

gui.forced_mouse_focus = false;
			}
			bool stopped = false;
			if (mouse_focus && mouse_focus->can_process()) {
				stopped = _gui_call_input(mouse_focus, mb);
			}
			if (stopped) {
				set_input_as_handled();
			}
		}
	}
	Ref<InputEventMouseMotion> mm = p_event;
	if (mm.is_valid()) {
		gui.key_event_accepted = false;
		Point2 mpos = mm->get_position();
		
		if (!gui.drag_attempted && gui.mouse_focus && (mm->get_button_mask().has_flag(MouseButtonMask::LEFT))) {
			gui.drag_accum += mm->get_relative();
			float len = gui.drag_accum.length();
			if (len > 10) {
				{ 
					CanvasItem *ci = gui.mouse_focus;
					while (ci) {
						Control *control = Object::cast_to<Control>(ci);
						if (control) {
							gui.dragging = true;
							gui.drag_data = control->get_drag_data(control->get_global_transform_with_canvas().affine_inverse().xform(mpos - gui.drag_accum));
							if (gui.drag_data.get_type() != Variant::NIL) {
								gui.mouse_focus = nullptr;
								gui.forced_mouse_focus = false;