fixes hyperspace connect_loc_behalf bug (#60231)

turns out my move_stacks var doesnt work asynchronously since this bug made things with connect_loc_behalf runtime on every movement unless you somehow moved it back to the transit turf and off without it doing the runtime special.

(The sleep and hell the whole bit of code in space/Entered was unneeded, since it just happens normally as a part of move. Life is pain) -Lemon

also does misc code improvements i found while investigating ANOTHER c_l_b bug with stacks i found while testing this one, which i did NOT manage to fix unfortunately

code/datums/components/slippery.dm

@@ -96,8 +96,9 @@
 	SIGNAL_HANDLER
 
 	UnregisterSignal(user, COMSIG_PARENT_PREQDELETED)
-	RemoveElement(/datum/element/connect_loc_behalf, holder, holder_connections)
-	holder = null
+	if(holder)
+		RemoveElement(/datum/element/connect_loc_behalf, holder, holder_connections)
+		holder = null
 
 /*
  * The slip proc, but for equipped items.

code/datums/materials/_material.dm

@@ -89,7 +89,7 @@ Simple datum which is instanced once per type and is used for every object of sa
 	if(istype(source, /obj)) //objs
 		on_applied_obj(source, amount, material_flags)
 
-	if(istype(source, /turf)) //turfs
+	else if(istype(source, /turf)) //turfs
 		on_applied_turf(source, amount, material_flags)
 
 	source.mat_update_desc(src)

code/game/turfs/open/space/space.dm

@@ -198,11 +198,6 @@
 			puller = pulling
 			pulling = next_pulling
 
-		//now we're on the new z_level, proceed the space drifting
-		stoplag()//Let a diagonal move finish, if necessary
-		arrived.newtonian_move(arrived.inertia_dir)
-		arrived.inertia_moving = TRUE
-
 
 /turf/open/space/MakeSlippery(wet_setting, min_wet_time, wet_time_to_add, max_wet_time, permanent)
 	return

code/game/turfs/open/space/transit.dm

@@ -32,7 +32,6 @@
 		throw_atom(arrived)
 
 /turf/open/space/transit/proc/throw_atom(atom/movable/AM)
-	set waitfor = FALSE
 	if(!AM || istype(AM, /obj/docking_port) || istype(AM, /obj/effect/abstract))
 		return
 	if(AM.loc != src) // Multi-tile objects are "in" multiple locs but its loc is it's true placement.

code/modules/mob/inventory.dm

@@ -158,7 +158,7 @@
 
 	if(isturf(I.loc) && !ignore_anim)
 		I.do_pickup_animation(src)
-	if(get_item_for_held_index(hand_index) != null)
+	if(get_item_for_held_index(hand_index))
 		dropItemToGround(get_item_for_held_index(hand_index), force = TRUE)
 	I.forceMove(src)
 	held_items[hand_index] = I

code/modules/mob/living/carbon/carbon_update_icons.dm

@@ -57,9 +57,8 @@
 		if(client && hud_used && hud_used.hud_version != HUD_STYLE_NOHUD)
 			I.screen_loc = ui_hand_position(get_held_index_of_item(I))
 			client.screen += I
-			if(observers?.len)
-				for(var/M in observers)
-					var/mob/dead/observe = M
+			if(length(observers))
+				for(var/mob/dead/observe as anything in observers)
 					if(observe.client && observe.client.eye == src)
 						observe.client.screen += I
 					else