fixes vampire executing nested marines (#6458)

# About the pull request
Resolves #6453 

# Explain why it's good for the game
bug bad

# Changelog
:cl:
fix: fixes vampire being able to execute hugged marines
/:cl:

---------

Co-authored-by: DOOM <N/A>

code/modules/mob/living/carbon/xenomorph/abilities/lurker/lurker_powers.dm

@@ -341,6 +341,12 @@
 	if(xeno.action_busy)
 		return
 
+	if(target_carbon.status_flags & XENO_HOST)
+		for(var/obj/item/alien_embryo/embryo in target_carbon)
+			if(HIVE_ALLIED_TO_HIVE(xeno.hivenumber, embryo.hivenumber))
+				to_chat(xeno, SPAN_WARNING("We should not harm this host! It has a sister inside."))
+				return
+
 	xeno.visible_message(SPAN_DANGER("[xeno] grabs [target_carbon]’s head aggressively."), \
 	SPAN_XENOWARNING("We grab [target_carbon]’s head aggressively."))