### Godot version

4.0.3.stable

### System information

Windows 10/11

### Issue description

I want the player's cursor to change when highlighting pickable Area2Ds; to do this, I have the areas modify the `mouse_default_cursor_shape` property on an external Control when the mouse enters or exits. If another Control appears in front of the Area2D while the mouse is over it, there is a chance that the project will crash.

Nothing prints to the IDE's output on this crash. If running the editor with console, then
```
ERROR: Condition "slot >= slot_max" is true. Returning: nullptr
   at: get_instance (./core/object/object.h:972)
```
will sometimes appear alongside the crash. If it appears, it always appears twice.

When I run a debug build of the editor through WinDbg, WinDbg will catch the following exception:
```
(3b58.2aac): Access violation - code c0000005 (!!! second chance !!!)
godot_windows_editor_x86_64!ObjectDB::get_instance [inlined in godot_windows_editor_x86_64!Viewport::_cleanup_mouseover_colliders+0x6f]:
00007ff6`ac254a1f 488b5310        mov     rdx,qword ptr [rbx+10h] ds:cccccccc`c31c419b=????????????????
```
When using this method, the exception is not random; it always occurs on the first attempt.

### Steps to reproduce

- Open the minimal reproduction project in the editor.
- Run the project.
- Click on the Area2D (you'll want visible collision shapes on).
- A full-screen button will pop up. If the game does not crash at this point, clicking the button will hide it so you can try again. It should crash within a few seconds of mashing.

### Minimal reproduction project

[Crash Test.zip](https://github.com/godotengine/godot/files/12027772/Crash.Test.zip)

mm->set_device(InputEvent::DEVICE_ID_INTERNAL);
		mm->set_position(get_mouse_position());
		mm->set_global_position(mm->get_position());
		mm->set_alt_pressed(Input::get_singleton()->is_key_pressed(Key::ALT));
		mm->set_shift_pressed(Input::get_singleton()->is_key_pressed(Key::SHIFT));
		mm->set_ctrl_pressed(Input::get_singleton()->is_key_pressed(Key::CTRL));
		mm->set_meta_pressed(Input::get_singleton()->is_key_pressed(Key::META));
		mm->set_button_mask(Input::get_singleton()->get_mouse_button_mask());
		physics_picking_events.push_back(mm);
	}
	while (physics_picking_events.size()) {
		local_input_handled = false;
		Ref<InputEvent> ev = physics_picking_events.front()->get();
		physics_picking_events.pop_front();
		Vector2 pos;
		bool is_mouse = false;
		Ref<InputEventMouseMotion> mm = ev;
		if (mm.is_valid()) {
			pos = mm->get_position();
			is_mouse = true;
		}
		Ref<InputEventMouseButton> mb = ev;
		if (mb.is_valid()) {
			pos = mb->get_position();
			is_mouse = true;
		}
		Ref<InputEventScreenDrag> sd = ev;
		if (sd.is_valid()) {
			pos = sd->get_position();
		}