### 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)

gui.subwindow_resize_from_rect = r;
						gui.subwindow_drag_from = mb->get_position();
						gui.subwindow_drag = SUB_WINDOW_DRAG_RESIZE;
						click_on_window = true;
					}
				}
			}
			if (!click_on_window && r.has_point(mb->get_position())) {
				
				if (gui.subwindow_focused != sw.window) {
					
					_sub_window_grab_focus(sw.window);
				}
				click_on_window = true;
			}
			if (click_on_window) {
				break;
			}
		}
		if (!click_on_window && gui.subwindow_focused) {
			
			_sub_window_grab_focus(nullptr);
		}
	}
	if (gui.subwindow_focused) {
		Ref<InputEventMouseMotion> mm = p_event;
		if (mm.is_valid()) {
			SubWindowResize resize = _sub_window_get_resize_margin(gui.subwindow_focused, mm->get_position());
			if (resize != SUB_WINDOW_RESIZE_DISABLED) {
				DisplayServer::CursorShape shapes[SUB_WINDOW_RESIZE_MAX] = {