### 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)

StringName shortcut_input_group;
	StringName unhandled_input_group;
	StringName unhandled_key_input_group;
	void _update_audio_listener_2d();
	bool disable_3d = false;
	void _propagate_viewport_notification(Node *p_node, int p_what);
	void _update_global_transform();
	RID texture_rid;
	DebugDraw debug_draw = DEBUG_DRAW_DISABLED;
	int positional_shadow_atlas_size = 2048;
	bool positional_shadow_atlas_16_bits = true;
	PositionalShadowAtlasQuadrantSubdiv positional_shadow_atlas_quadrant_subdiv[4];
	MSAA msaa_2d = MSAA_DISABLED;
	MSAA msaa_3d = MSAA_DISABLED;
	ScreenSpaceAA screen_space_aa = SCREEN_SPACE_AA_DISABLED;
	bool use_taa = false;
	Scaling3DMode scaling_3d_mode = SCALING_3D_MODE_BILINEAR;
	float scaling_3d_scale = 1.0;
	float fsr_sharpness = 0.2f;
	float texture_mipmap_bias = 0.0f;
	bool use_debanding = false;
	float mesh_lod_threshold = 1.0;
	bool use_occlusion_culling = false;
	Ref<ViewportTexture> default_texture;
	HashSet<ViewportTexture *> viewport_textures;
	void _update_viewport_path();
	SDFOversize sdf_oversize = SDF_OVERSIZE_120_PERCENT;
	SDFScale sdf_scale = SDF_SCALE_50_PERCENT;
	uint32_t canvas_cull_mask = 0xffffffff; 
	enum SubWindowDrag {