[MIRROR] Violent debraining no longer strands clients [MDB IGNORE] (#23378)

* Violent debraining no longer strands clients (#77959)

## About The Pull Request
Man this took me forever to diagnose.

Currently, when debraining a dismembered head, the brain doesn't
properly get its brainmob set. This both prevents the brain from being
usable even in MMI's, displaying a devoid of life message, and sends an
admin log that the brainmob was stranded.

This fixes both that and a nearby runtime that I encountered while
testing.
I believe introduced by #77339 when handle_atom_del's code was switched
to run whenever anything exited the head instead of just when deleted
## Why It's Good For The Game
Fix bugs! Stranded clients very bad
## Changelog
🆑
fix: Non-surgically debraining someone no longer makes their brain
unusuable
/🆑

* Violent debraining no longer strands clients

---------

Co-authored-by: FlufflesTheDog <piecopresident@gmail.com>

code/modules/surgery/bodyparts/head.dm

@@ -165,7 +165,6 @@
 				user.visible_message(span_warning("[user] saws [src] open and pulls out a brain!"), span_notice("You saw [src] open and pull out a brain."))
 			if(brainmob)
 				brainmob.container = null
-				brainmob.forceMove(brain)
 				brain.brainmob = brainmob
 				brainmob = null
 			if(violent_removal && prob(rand(80, 100))) //ghetto surgery can damage the brain.
@@ -191,7 +190,8 @@
 
 /obj/item/bodypart/head/update_limb(dropping_limb, is_creating)
 	. = ..()
-	real_name = owner.real_name
+	if(!isnull(owner))
+		real_name = owner.real_name
 	if(HAS_TRAIT(owner, TRAIT_HUSK))
 		real_name = "Unknown"
 	update_hair_and_lips(dropping_limb, is_creating)