Improves glock code - fixes glock sprite when empty

Created by: SonixApache

Glock port was shit, lot of parts were just copied over without checking how they work on our code. Also changed the check for the update icon, so now the slide'll only pop back when there's no bullets (but it doesn't show if a mag is loaded or not.) Might add a little LED or something in a future PR.

fixes #12042 (closed)