### 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)

ERR_MAIN_THREAD_GUARD;
	if (camera_3d_override) {
		camera_3d_override.transform = p_transform;
		RenderingServer::get_singleton()->camera_set_transform(camera_3d_override.rid, p_transform);
	}
}
Transform3D Viewport::get_camera_3d_override_transform() const {
	ERR_READ_THREAD_GUARD_V(Transform3D());
	if (camera_3d_override) {
		return camera_3d_override.transform;
	}
	return Transform3D();
}
Ref<World3D> Viewport::get_world_3d() const {
	ERR_READ_THREAD_GUARD_V(Ref<World3D>());
	return world_3d;
}
Ref<World3D> Viewport::find_world_3d() const {
	ERR_READ_THREAD_GUARD_V(Ref<World3D>());
	if (own_world_3d.is_valid()) {
		return own_world_3d;
	} else if (world_3d.is_valid()) {
		return world_3d;
	} else if (parent) {
		return parent->find_world_3d();
	} else {
		return Ref<World3D>();
	}
}
void Viewport::set_world_3d(const Ref<World3D> &p_world_3d) {