External Bleeding Sealing in Cryo Tubes (#6175)

# About the pull request

This PR is sort of a follow up to #6058 expanding on the bleeding stop
effect for cryotubes allowing them to also seal external bleeding.

Since internal bleeding did not cap the reduction in blood loss, it
could underflow resulting in blood being added for the last tick. This
is now fixed.

# Explain why it's good for the game

Cryotubes already cure IB when cryo chemicals are used because of the
patient reaching low temperatures, so I see little reason why the effect
wouldn't also occur for external bleeding if you're in a cryotube.

# Testing Photographs and Procedure
<details>
<summary>Screenshots & Videos</summary>


https://github.com/cmss13-devs/cmss13/assets/76988376/7dffed9b-051c-4cfc-9c01-7314766d5d15

</details>


# Changelog
:cl:
balance: Cryotubes now also cure external bleeding
fix: Fixed internal bleeding granting blood on its last tick
/:cl:

code/datums/effects/bleeding.dm

@@ -71,6 +71,11 @@
 			if(affected_mob.reagents.get_reagent_amount("thwei"))
 				blood_loss -= THWEI_BLOOD_REDUCTION
 
+			if(affected_mob.bodytemperature < T0C && (affected_mob.reagents.get_reagent_amount("cryoxadone") || affected_mob.reagents.get_reagent_amount("clonexadone")))
+				var/obj/structure/machinery/cryo_cell/cryo = affected_mob.loc
+				if(istype(cryo) && cryo.on && cryo.operable())
+					blood_loss -= CRYO_BLOOD_REDUCTION
+
 			var/mob/living/carbon/human/affected_human = affected_mob
 			if(istype(affected_human))
 				if(affected_human.chem_effect_flags & CHEM_EFFECT_NO_BLEEDING)
@@ -95,18 +100,19 @@
 	if(affected_mob.in_stasis == STASIS_IN_BAG)
 		return FALSE
 
-	if(affected_mob.bodytemperature < T0C && (affected_mob.reagents && affected_mob.reagents.get_reagent_amount("cryoxadone") || affected_mob.reagents.get_reagent_amount("clonexadone")))
-		blood_loss -= CRYO_BLOOD_REDUCTION
-
 	if(affected_mob.reagents) // Annoying QC check
 		if(affected_mob.reagents.get_reagent_amount("thwei"))
 			blood_loss -= THWEI_BLOOD_REDUCTION
 
+		if(affected_mob.bodytemperature < T0C && (affected_mob.reagents.get_reagent_amount("cryoxadone") || affected_mob.reagents.get_reagent_amount("clonexadone")))
+			blood_loss -= CRYO_BLOOD_REDUCTION
+
 		var/mob/living/carbon/human/affected_human = affected_mob
 		if(istype(affected_human))
 			if(affected_human.chem_effect_flags & CHEM_EFFECT_NO_BLEEDING)
 				return FALSE
 
+	blood_loss = max(blood_loss, 0) // Bleeding shouldn't give extra blood even if its only 1 tick
 	affected_mob.blood_volume = max(affected_mob.blood_volume - blood_loss, 0)
 
 	return TRUE