### 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)

if (co && co->can_process()) {
						new_collider = result.collider_id;
						if (!capture_object) {
							last_object = co;
							last_id = result.collider_id;
							if (co->get_capture_input_on_drag() && mb.is_valid() && mb->get_button_index() == MouseButton::LEFT && mb->is_pressed()) {
								physics_object_capture = last_id;
							}
						}
					}
					if (is_mouse && new_collider != physics_object_over) {
						if (physics_object_over.is_valid()) {
							CollisionObject3D *previous_co = Object::cast_to<CollisionObject3D>(ObjectDB::get_instance(physics_object_over));
							if (previous_co) {
								previous_co->_mouse_exit();
							}
						}
						if (new_collider.is_valid()) {
							DEV_ASSERT(co);
							co->_mouse_enter();
						}
						physics_object_over = new_collider;
					}
					if (capture_object) {
						_collision_object_3d_input_event(capture_object, camera_3d, ev, result.position, result.normal, result.shape);
					} else if (new_collider.is_valid()) {
						_collision_object_3d_input_event(co, camera_3d, ev, result.position, result.normal, result.shape);
					}
				}
				last_pos = pos;