### 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_FAIL_COND(p_event.is_null());
	if (!is_editable()) {
		return;
	}
	Ref<InputEventMouseButton> mb = p_event;
	double step = get_custom_arrow_step() != 0.0 ? get_custom_arrow_step() : get_step();
	if (mb.is_valid() && mb->is_pressed()) {
		bool up = mb->get_position().y < (get_size().height / 2);
		switch (mb->get_button_index()) {
			case MouseButton::LEFT: {
				line_edit->grab_focus();
				set_value(get_value() + (up ? step : -step));
				range_click_timer->set_wait_time(0.6);
				range_click_timer->set_one_shot(true);
				range_click_timer->start();
				drag.allowed = true;
				drag.capture_pos = mb->get_position();
			} break;
			case MouseButton::RIGHT: {
				line_edit->grab_focus();
				set_value((up ? get_max() : get_min()));
			} break;
			case MouseButton::WHEEL_UP: {
				if (line_edit->has_focus()) {
					set_value(get_value() + step * mb->get_factor());
					accept_event();
				}
			} break;
			case MouseButton::WHEEL_DOWN: {
				if (line_edit->has_focus()) {