### 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 (over) {
			bool stopped = false;
			if (over->can_process()) {
				Transform2D localizer = over->get_global_transform_with_canvas().affine_inverse();
				Size2 pos = localizer.xform(drag_event->get_position());
				Vector2 velocity = localizer.basis_xform(drag_event->get_velocity());
				Vector2 rel = localizer.basis_xform(drag_event->get_relative());
				drag_event = drag_event->xformed_by(Transform2D()); 
				drag_event->set_velocity(velocity);
				drag_event->set_relative(rel);
				drag_event->set_position(pos);
				stopped = _gui_call_input(over, drag_event);
			}
			if (stopped) {
				set_input_as_handled();
			}
			return;
		}
	}
	if (mm.is_null() && mb.is_null() && p_event->is_action_type()) {
		if (gui.dragging && p_event->is_action_pressed("ui_cancel") && Input::get_singleton()->is_action_just_pressed("ui_cancel")) {
			_perform_drop();
			set_input_as_handled();
			return;
		}
		if (gui.key_focus && !gui.key_focus->is_visible_in_tree()) {
			gui.key_focus->release_focus();
		}
		if (gui.key_focus) {
			gui.key_event_accepted = false;