[MIRROR] Self-used fulton extraction packs autostoring in any back storage [MDB IGNORE] (#21587)

* Self-used fulton extraction packs autostoring in any back storage (#75763)

## About The Pull Request

when fultoning yourself, adjusts the fulton autobag check from "is there
a backpack on this guy" to "can we try shoving stuff into their
back-slot item's atom storage"

not sure if this is qol, fix, or god forbid balance but let's go with
the maybe least offensive option first

...if it was an oversight can i legally flag this as a fix?
closes #75327
## Why It's Good For The Game
makes the autobagging feature work for other back-mounted storage
options. like MODs.

![image](https://github.com/tgstation/tgstation/assets/31829017/47b3d7f7-d042-465a-b3e0-11c8e7c3cb0b)
## Changelog

🆑
qol: Fulton extraction packs (when used on yourself) now automatically
shove themselves into any back-mounted storage, like MODsuit storage
modules.
/🆑

Co-authored-by: Hatterhat <Hatterhat@ users.noreply.github.com>

* Self-used fulton extraction packs autostoring in any back storage

---------

Co-authored-by: Hatterhat <31829017+Hatterhat@users.noreply.github.com>
Co-authored-by: Hatterhat <Hatterhat@ users.noreply.github.com>

code/modules/mining/fulton.dm

@@ -62,9 +62,8 @@ GLOBAL_LIST_EMPTY(total_extraction_beacons)
 		to_chat(user, span_notice("You start attaching the pack to [A]..."))
 		if(do_after(user,50,target=A))
 			to_chat(user, span_notice("You attach the pack to [A] and activate it."))
-			if(loc == user && istype(user.back, /obj/item/storage/backpack))
-				var/obj/item/storage/backpack/B = user.back
-				B.atom_storage?.attempt_insert(src, user)
+			if(loc == user)
+				user.back?.atom_storage?.attempt_insert(src, user)
 			uses_left--
 			if(uses_left <= 0)
 				user.transferItemToLoc(src, A, TRUE)