### 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)

line_edit = memnew(LineEdit);
	add_child(line_edit, false, INTERNAL_MODE_FRONT);
	line_edit->set_anchors_and_offsets_preset(Control::PRESET_FULL_RECT);
	line_edit->set_mouse_filter(MOUSE_FILTER_PASS);
	line_edit->set_horizontal_alignment(HORIZONTAL_ALIGNMENT_LEFT);
	line_edit->connect("text_submitted", callable_mp(this, &SpinBox::_text_submitted), CONNECT_DEFERRED);
	line_edit->connect("focus_entered", callable_mp(this, &SpinBox::_line_edit_focus_enter), CONNECT_DEFERRED);
	line_edit->connect("focus_exited", callable_mp(this, &SpinBox::_line_edit_focus_exit), CONNECT_DEFERRED);
	line_edit->connect("gui_input", callable_mp(this, &SpinBox::_line_edit_input));
	range_click_timer = memnew(Timer);
	range_click_timer->connect("timeout", callable_mp(this, &SpinBox::_range_click_timeout));
	add_child(range_click_timer, false, INTERNAL_MODE_FRONT);
}