### 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_READ_THREAD_GUARD_V(0);
	return mesh_lod_threshold;
}
void Viewport::set_use_occlusion_culling(bool p_use_occlusion_culling) {
	ERR_MAIN_THREAD_GUARD;
	if (use_occlusion_culling == p_use_occlusion_culling) {
		return;
	}
	use_occlusion_culling = p_use_occlusion_culling;
	RS::get_singleton()->viewport_set_use_occlusion_culling(viewport, p_use_occlusion_culling);
	notify_property_list_changed();
}
bool Viewport::is_using_occlusion_culling() const {
	ERR_READ_THREAD_GUARD_V(false);
	return use_occlusion_culling;
}
void Viewport::set_debug_draw(DebugDraw p_debug_draw) {
	ERR_MAIN_THREAD_GUARD;
	debug_draw = p_debug_draw;
	RS::get_singleton()->viewport_set_debug_draw(viewport, RS::ViewportDebugDraw(p_debug_draw));
}
Viewport::DebugDraw Viewport::get_debug_draw() const {
	ERR_READ_THREAD_GUARD_V(DEBUG_DRAW_DISABLED);
	return debug_draw;
}
int Viewport::get_render_info(RenderInfoType p_type, RenderInfo p_info) {