Synctest session doesn't detect all desyncs that it could/should #108

Describe the bug

If the user forgets to register a component for rollback, this may cause a problem when the entity is despawned which is not detected by synctest sessions.

For instance. Let's say the user forgets to register a marker component, Bullet.

If a system despawns the bullet:

fn despawn_bullets(
    mut commands: Commands,
    bullets: Query<Entity, With<Bullet>>,
) {
    for bullet in &bullets {
        info!("despawning bullet {bullet:?}");
        commands.entity(bullet).despawn_recursive();
    }
}

This is desync bug, because restoring the bullet entity will not restore the Bullet component.

However, this is not detected by the synctest session. It happily restores the bullet entity without the Bullet component and doesn't report any desyncs.

It looks like the synctest session rolls back before it stores the latest checksum. It might be that something is wrong wrt the order we do things.

To Reproduce

1. Check out https://github.com/johanhelsing/extreme_bevy/tree/bevy-ggrs-synctest-bug
2. run it with --synctest
3. Kill one player to trigger a new round

Bullets remain on screen, likely without the Bullet component, and no desync errors are printed

Expected behavior

Running the synctest session should trigger an error