### 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)

#include "spin_box.h"
#include "core/input/input.h"
#include "core/math/expression.h"
Size2 SpinBox::get_minimum_size() const {
	Size2 ms = line_edit->get_combined_minimum_size();
	ms.width += last_w;
	return ms;
}
void SpinBox::_update_text() {
	String value = String::num(get_value(), Math::range_step_decimals(get_step()));
	if (is_localizing_numeral_system()) {
		value = TS->format_number(value);
	}
	if (!line_edit->has_focus()) {
		if (!prefix.is_empty()) {
			value = prefix + " " + value;
		}
		if (!suffix.is_empty()) {
			value += " " + suffix;
		}
	}
	line_edit->set_text(value);
}
void SpinBox::_text_submitted(const String &p_string) {