### 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)

DisplayServer::CURSOR_ARROW,
					DisplayServer::CURSOR_FDIAGSIZE,
					DisplayServer::CURSOR_VSIZE,
					DisplayServer::CURSOR_BDIAGSIZE,
					DisplayServer::CURSOR_HSIZE,
					DisplayServer::CURSOR_HSIZE,
					DisplayServer::CURSOR_BDIAGSIZE,
					DisplayServer::CURSOR_VSIZE,
					DisplayServer::CURSOR_FDIAGSIZE
				};
				if (DisplayServer::get_singleton()->has_feature(DisplayServer::FEATURE_CURSOR_SHAPE)) {
					DisplayServer::get_singleton()->cursor_set_shape(shapes[resize]);
				}
				return true; 
			}
		}
	}
	if (gui.subwindow_drag != SUB_WINDOW_DRAG_DISABLED) {
		return true; 
	}
	if (!gui.subwindow_focused) {
		return false;
	}
	Transform2D window_ofs;
	window_ofs.set_origin(-gui.subwindow_focused->get_position());
	Ref<InputEvent> ev = p_event->xformed_by(window_ofs);
	gui.subwindow_focused->_window_input(ev);
	return true;
}
void Viewport::push_input(const Ref<InputEvent> &p_event, bool p_local_coords) {