Fixes runtime with the infective component on gibs (#70706)

* Fixes runtime with the infective component. streak_diseases is a lazylist and is sometimes not instantiated.

* Lazynull

code/datums/components/infective.dm

@@ -117,6 +117,10 @@
 /datum/component/infective/proc/try_infect_streak(datum/source, list/directions, list/output_diseases)
 	SIGNAL_HANDLER
 
+	// This blood is not infectable / does not have a diseases list
+	if(!islist(output_diseases))
+		return
+
 	output_diseases |= diseases
 
 /datum/component/infective/proc/try_infect(mob/living/L, target_zone)

code/game/objects/effects/decals/cleanable/humans.dm

@@ -116,6 +116,10 @@
 	. = ..()
 	RegisterSignal(src, COMSIG_MOVABLE_PIPE_EJECTING, .proc/on_pipe_eject)
 
+/obj/effect/decal/cleanable/blood/gibs/Destroy()
+	LAZYNULL(streak_diseases)
+	return ..()
+
 /obj/effect/decal/cleanable/blood/gibs/replace_decal(obj/effect/decal/cleanable/C)
 	return FALSE //Never fail to place us
 
@@ -145,9 +149,9 @@
 	streak(dirs)
 
 /obj/effect/decal/cleanable/blood/gibs/proc/streak(list/directions, mapload=FALSE)
+	LAZYINITLIST(streak_diseases)
 	SEND_SIGNAL(src, COMSIG_GIBS_STREAK, directions, streak_diseases)
 	var/direction = pick(directions)
-	streak_diseases = list()
 	var/delay = 2
 	var/range = pick(0, 200; 1, 150; 2, 50; 3, 17; 50) //the 3% chance of 50 steps is intentional and played for laughs.
 	if(!step_to(src, get_step(src, direction), 0))