### 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)

if (first == nullptr || first->is_greater_than(E)) {
						first = E;
					}
				}
				if (first) {
					first->make_current();
				}
			}
#endif 
		} break;
		case NOTIFICATION_EXIT_TREE: {
			_gui_cancel_tooltip();
			RenderingServer::get_singleton()->viewport_set_scenario(viewport, RID());
			RenderingServer::get_singleton()->viewport_remove_canvas(viewport, current_canvas);
			if (contact_2d_debug.is_valid()) {
				RenderingServer::get_singleton()->free(contact_2d_debug);
				contact_2d_debug = RID();
			}
			if (contact_3d_debug_multimesh.is_valid()) {
				RenderingServer::get_singleton()->free(contact_3d_debug_multimesh);
				RenderingServer::get_singleton()->free(contact_3d_debug_instance);
				contact_3d_debug_instance = RID();
				contact_3d_debug_multimesh = RID();
			}
			remove_from_group("_viewports");
			set_physics_process_internal(false);
			RS::get_singleton()->viewport_set_active(viewport, false);
			RenderingServer::get_singleton()->viewport_set_parent_viewport(viewport, RID());
		} break;
		case NOTIFICATION_PATH_RENAMED: {