### 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)

next = from->_get_focus_neighbor(SIDE_BOTTOM);
				}
			} else {
				if (p_event->is_action_pressed("ui_focus_next", true, true)) {
					next = from->find_next_valid_focus();
				}
				if (p_event->is_action_pressed("ui_focus_prev", true, true)) {
					next = from->find_prev_valid_focus();
				}
				if (p_event->is_action_pressed("ui_up", true, true)) {
					next = from->_get_focus_neighbor(SIDE_TOP);
				}
				if (p_event->is_action_pressed("ui_left", true, true)) {
					next = from->_get_focus_neighbor(SIDE_LEFT);
				}
				if (p_event->is_action_pressed("ui_right", true, true)) {
					next = from->_get_focus_neighbor(SIDE_RIGHT);
				}
				if (p_event->is_action_pressed("ui_down", true, true)) {
					next = from->_get_focus_neighbor(SIDE_BOTTOM);
				}
			}
			if (next) {
				next->grab_focus();
				set_input_as_handled();
			}
		}
	}
}
void Viewport::_perform_drop(Control *p_control, Point2 p_pos) {