Foam darts and other unembeddable bullets will no longer leave ghost shrapnel (#54994)

Projectiles are assigned the ability to try embedding by the presence of a shrapnel_type variable being set on them, whether or not they actually have a set of embedding stats in their embedding var. By default, children of /obj/projectile/bullet have a shrapnel type set to a generic embedded bullet item, including things like foam darts and lollypop projectiles which shouldn't be able to embed (and certainly not embed as a bullet). While they had their embedding vars set to null, they still had their shrapnel_type set to the embedded bullet type, meaning shooting a person with a dart gun or whatever would leave a failed shrapnel item on the ground where they weren't supposed to.

This fixes that by requiring both a defined shrapnel_type AND a defined embedding var for the embedding stats. Any projectiles without both won't be able to try embedding. I also manually put 'shrapnel_type = null' on any bullet subtypes with embedding = null just to be safe and for consistency.

code/game/objects/items/robot/robot_items.dm

@@ -532,7 +532,6 @@
 	desc = "Oh noes! A fast-moving lollipop!"
 	icon_state = "lollipop_1"
 	ammo_type = /obj/item/food/chewable/lollipop/cyborg
-	embedding = null
 	nodamage = TRUE
 	damage = 0
 	speed = 0.5

code/modules/projectiles/projectile.dm

@@ -443,7 +443,7 @@
 	if(fired_from)
 		SEND_SIGNAL(fired_from, COMSIG_PROJECTILE_BEFORE_FIRE, src, original)
 	//If no angle needs to resolve it from xo/yo!
-	if(shrapnel_type)
+	if(shrapnel_type && LAZYLEN(embedding))
 		AddElement(/datum/element/embed, projectile_payload = shrapnel_type)
 	if(!log_override && firer && original)
 		log_combat(firer, original, "fired at", src, "from [get_area_name(src, TRUE)]")

code/modules/projectiles/projectile/bullets/dart_syringe.dm

@@ -3,6 +3,7 @@
 	icon_state = "cbbolt"
 	damage = 6
 	embedding = null
+	shrapnel_type = null
 	var/piercing = FALSE
 
 /obj/projectile/bullet/dart/Initialize()

code/modules/projectiles/projectile/bullets/dnainjector.dm

@@ -5,6 +5,7 @@
 	damage = 5
 	hitsound_wall = "shatter"
 	embedding = null
+	shrapnel_type = null
 
 /obj/projectile/bullet/dnainjector/on_hit(atom/target, blocked = FALSE)
 	if(iscarbon(target))

code/modules/projectiles/projectile/bullets/grenade.dm

@@ -6,6 +6,7 @@
 	icon_state= "bolter"
 	damage = 60
 	embedding = null
+	shrapnel_type = null
 
 /obj/projectile/bullet/a40mm/on_hit(atom/target, blocked = FALSE)
 	..()

code/modules/projectiles/projectile/bullets/pistol.dm

@@ -10,6 +10,7 @@
 	damage = 27
 	armour_penetration = 40
 	embedding = null
+	shrapnel_type = null
 
 /obj/projectile/bullet/c9mm_hp
 	name = "9mm hollow-point bullet"

code/modules/projectiles/projectile/bullets/revolver.dm

@@ -42,7 +42,7 @@
 	ricochet_incidence_leeway = 0
 	ricochet_chance = 130
 	ricochet_decay_damage = 0.8
-	shrapnel_type = NONE
+	shrapnel_type = null
 	sharpness = SHARP_NONE
 	embedding = null
 

code/modules/projectiles/projectile/bullets/special.dm

@@ -10,6 +10,7 @@
 	icon_state = "banana"
 	range = 200
 	embedding = null
+	shrapnel_type = null
 
 /obj/projectile/bullet/honker/Initialize()
 	. = ..()

code/modules/projectiles/projectile/reusable/_reusable.dm

@@ -1,10 +1,11 @@
 /obj/projectile/bullet/reusable
 	name = "reusable bullet"
 	desc = "How do you even reuse a bullet?"
-	var/ammo_type = /obj/item/ammo_casing/caseless
-	var/dropped = FALSE
 	impact_effect_type = null
 	embedding = null
+	shrapnel_type = null
+	var/ammo_type = /obj/item/ammo_casing/caseless
+	var/dropped = FALSE
 
 /obj/projectile/bullet/reusable/on_hit(atom/target, blocked = FALSE)
 	. = ..()

code/modules/projectiles/projectile/special/rocket.dm

@@ -3,6 +3,7 @@
 	icon_state= "bolter"
 	damage = 50
 	embedding = null
+	shrapnel_type = null
 
 /obj/projectile/bullet/gyro/on_hit(atom/target, blocked = FALSE)
 	..()
@@ -18,6 +19,7 @@
 	armour_penetration = 100
 	dismemberment = 100
 	embedding = null
+	shrapnel_type = null
 
 /obj/projectile/bullet/a84mm/on_hit(atom/target, blocked = FALSE)
 	..()
@@ -38,6 +40,7 @@
 	damage = 30
 	ricochets_max = 0 //it's a MISSILE
 	embedding = null
+	shrapnel_type = null
 
 /obj/projectile/bullet/a84mm_he/on_hit(atom/target, blocked=0)
 	..()
@@ -54,6 +57,7 @@
 	damage = 30
 	ricochets_max = 0 //it's a MISSILE
 	embedding = null
+	shrapnel_type = null
 	var/sturdy = list(
 	/turf/closed,
 	/obj/vehicle/sealed/mecha,