Fixes fire not stopping vamp healing (#8469)

# About the pull request

fixes #6921

# Explain why it's good for the game
bugfix/oversight

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

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# Changelog
:cl:
fix: Fixes fire not negating vampire healing
/:cl:

Co-authored-by: InsaneRed <[email protected]>

code/modules/mob/living/carbon/xenomorph/strains/castes/lurker/vampire.dm

@@ -101,8 +101,9 @@
 			log_attack("[key_name(xeno)] attacked [key_name(target)] with Flurry")
 			target.apply_armoured_damage(get_xeno_damage_slash(target, xeno.caste.melee_damage_upper), ARMOR_MELEE, BRUTE, rand_zone())
 			playsound(get_turf(target), 'sound/weapons/alien_claw_flesh4.ogg', 30, TRUE)
-			xeno.flick_heal_overlay(1 SECONDS, "#00B800")
-			xeno.gain_health(30)
+			if(!xeno.on_fire)
+				xeno.flick_heal_overlay(1 SECONDS, "#00B800")
+				xeno.gain_health(30)
 			xeno.animation_attack_on(target)
 
 	xeno.emote("roar")
@@ -261,9 +262,10 @@
 	xeno.animation_attack_on(target_carbon, pixel_offset = 16)
 	target_carbon.apply_armoured_damage(60, ARMOR_MELEE, BRUTE, "head", 5) //DIE
 	target_carbon.death(create_cause_data("headbite execution", xeno), FALSE)
-	xeno.gain_health(150)
-	xeno.xeno_jitter(1 SECONDS)
-	xeno.flick_heal_overlay(3 SECONDS, "#00B800")
+	if(!xeno.on_fire)
+		xeno.gain_health(150)
+		xeno.xeno_jitter(1 SECONDS)
+		xeno.flick_heal_overlay(3 SECONDS, "#00B800")
 	xeno.emote("roar")
 	log_attack("[key_name(xeno)] was executed by [key_name(target_carbon)] with a headbite!")
 	apply_cooldown()