### 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)

class Label;
class SceneTreeTimer;
class Viewport;
class Window;
class World2D;
class ViewportTexture : public Texture2D {
	GDCLASS(ViewportTexture, Texture2D);
	NodePath path;
	friend class Viewport;
	Viewport *vp = nullptr;
	bool vp_pending = false;
	void _setup_local_to_scene(const Node *p_loc_scene);
	mutable RID proxy_ph;
	mutable RID proxy;
protected:
	static void _bind_methods();
public:
	void set_viewport_path_in_scene(const NodePath &p_path);
	NodePath get_viewport_path_in_scene() const;
	virtual void setup_local_to_scene() override;
	virtual int get_width() const override;
	virtual int get_height() const override;
	virtual Size2 get_size() const override;
	virtual RID get_rid() const override;
	virtual bool has_alpha() const override;
	virtual Ref<Image> get_image() const override;
	ViewportTexture();
	~ViewportTexture();
};
class Viewport : public Node {