### 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)

bool _camera_3d_add(Camera3D *p_camera); 
	void _camera_3d_remove(Camera3D *p_camera);
	void _camera_3d_make_next_current(Camera3D *p_exclude);
	void enable_camera_3d_override(bool p_enable);
	bool is_camera_3d_override_enabled() const;
	void set_camera_3d_override_transform(const Transform3D &p_transform);
	Transform3D get_camera_3d_override_transform() const;
	void set_camera_3d_override_perspective(real_t p_fovy_degrees, real_t p_z_near, real_t p_z_far);
	void set_camera_3d_override_orthogonal(real_t p_size, real_t p_z_near, real_t p_z_far);
	void set_disable_3d(bool p_disable);
	bool is_3d_disabled() const;
	Ref<World3D> world_3d;
	Ref<World3D> own_world_3d;
	void set_world_3d(const Ref<World3D> &p_world_3d);
	Ref<World3D> get_world_3d() const;
	Ref<World3D> find_world_3d() const;
	void _own_world_3d_changed();
	void set_use_own_world_3d(bool p_use_own_world_3d);
	bool is_using_own_world_3d() const;
	void _propagate_enter_world_3d(Node *p_node);
	void _propagate_exit_world_3d(Node *p_node);
	void set_use_xr(bool p_use_xr);
	bool is_using_xr();
#endif 
	void _propagate_world_2d_changed(Node *p_node);
	void _validate_property(PropertyInfo &p_property) const;
	Viewport();
	~Viewport();
};
class SubViewport : public Viewport {