Fixes auto unloading for gate loaded revolvers (#3038)

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## About The Pull Request

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The bullet physics weren't getting all the parameters they needed when
unload_all_casings called eject_casing so the bullets never left the
chamber as a result. Fixes that.

## Why It's Good For The Game

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worth adding. -->

Bug fix good

## Changelog

:cl:
fix: Auto unloading for gate loaded revolvers
/:cl:

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code/modules/projectiles/guns/ballistic/revolver.dm

@@ -100,7 +100,7 @@
 			var/doafter_time = 0.4 SECONDS
 			if(!do_mob(user,user,doafter_time))
 				break
-			if(!eject_casing())
+			if(!eject_casing(user))
 				doafter_time = 0 SECONDS
 			else
 				num_unloaded++
@@ -122,6 +122,7 @@
 			to_chat(user, "<span class='warning'>There's nothing in the gate to eject from [src]!</span>")
 		return FALSE
 	playsound(src, eject_sound, eject_sound_volume, eject_sound_vary)
+	casing_to_eject.forceMove(drop_location())
 	var/angle_of_movement =(rand(-3000, 3000) / 100) + dir2angle(turn(user.dir, 180))
 	casing_to_eject.AddComponent(/datum/component/movable_physics, _horizontal_velocity = rand(350, 450) / 100, _vertical_velocity = rand(400, 450) / 100, _horizontal_friction = rand(20, 24) / 100, _z_gravity = PHYSICS_GRAV_STANDARD, _z_floor = 0, _angle_of_movement = angle_of_movement)
 
@@ -279,7 +280,6 @@
 		playsound(src, rack_sound, rack_sound_volume, rack_sound_vary)
 
 	chamber_round(TRUE)
-	//playsound(src, rack_sound, rack_sound_volume, rack_sound_vary)
 	SEND_SIGNAL(src, COMSIG_UPDATE_AMMO_HUD)
 	update_appearance()