### 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)

#ifndef _3D_DISABLED
				PhysicsServer3D::get_singleton()->space_set_debug_contacts(find_world_3d()->get_space(), get_tree()->get_collision_debug_contact_count());
				contact_3d_debug_multimesh = RenderingServer::get_singleton()->multimesh_create();
				RenderingServer::get_singleton()->multimesh_allocate_data(contact_3d_debug_multimesh, get_tree()->get_collision_debug_contact_count(), RS::MULTIMESH_TRANSFORM_3D, false);
				RenderingServer::get_singleton()->multimesh_set_visible_instances(contact_3d_debug_multimesh, 0);
				RenderingServer::get_singleton()->multimesh_set_mesh(contact_3d_debug_multimesh, get_tree()->get_debug_contact_mesh()->get_rid());
				contact_3d_debug_instance = RenderingServer::get_singleton()->instance_create();
				RenderingServer::get_singleton()->instance_set_base(contact_3d_debug_instance, contact_3d_debug_multimesh);
				RenderingServer::get_singleton()->instance_set_scenario(contact_3d_debug_instance, find_world_3d()->get_scenario());
				RenderingServer::get_singleton()->instance_geometry_set_flag(contact_3d_debug_instance, RS::INSTANCE_FLAG_DRAW_NEXT_FRAME_IF_VISIBLE, true);
#endif 
				set_physics_process_internal(true);
			}
		} break;
		case NOTIFICATION_READY: {
#ifndef _3D_DISABLED
			if (audio_listener_3d_set.size() && !audio_listener_3d) {
				AudioListener3D *first = nullptr;
				for (AudioListener3D *E : audio_listener_3d_set) {
					if (first == nullptr || first->is_greater_than(E)) {
						first = E;
					}
				}
				if (first) {
					first->make_current();
				}
			}
			if (camera_3d_set.size() && !camera_3d) {
				
				Camera3D *first = nullptr;