Eggs are now properly converted to forsaken on evac (#5340)

# About the pull request
half of #4376 
eggs now become forsaken on hijack, like everything else. tested and it
works.


# Explain why it's good for the game

bugs should be fixed


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

Put screenshots and videos here with an empty line between the
screenshots and the `<details>` tags.

</details>


# Changelog
:cl: Private Tristan
fix: Eggs are properly converted to Forsaken hive on evac
/:cl:

code/modules/cm_aliens/structures/egg.dm

@@ -23,10 +23,21 @@
 	if (hive)
 		hivenumber = hive
 
+	if(hivenumber == XENO_HIVE_NORMAL)
+		RegisterSignal(SSdcs, COMSIG_GLOB_GROUNDSIDE_FORSAKEN_HANDLING, PROC_REF(forsaken_handling))
+
 	set_hive_data(src, hivenumber)
 	update_icon()
 	addtimer(CALLBACK(src, PROC_REF(Grow)), rand(EGG_MIN_GROWTH_TIME, EGG_MAX_GROWTH_TIME))
 
+/obj/effect/alien/egg/proc/forsaken_handling()
+	SIGNAL_HANDLER
+	if(is_ground_level(z))
+		hivenumber = XENO_HIVE_FORSAKEN
+		set_hive_data(src, XENO_HIVE_FORSAKEN)
+
+	UnregisterSignal(SSdcs, COMSIG_GLOB_GROUNDSIDE_FORSAKEN_HANDLING)
+
 /obj/effect/alien/egg/Destroy()
 	. = ..()
 	for(var/obj/effect/egg_trigger/trigger as anything in egg_triggers)

code/modules/mob/living/carbon/xenomorph/abilities/ability_helper_procs.dm

@@ -31,7 +31,6 @@
 	if(isobj(O))
 		I = O
 
-
 		wait_time = I.get_applying_acid_time()
 		if(wait_time == -1)
 			to_chat(src, SPAN_WARNING("We cannot dissolve \the [I]."))

code/modules/mob/living/carbon/xenomorph/egg_item.dm

@@ -25,6 +25,17 @@
 	set_hive_data(src, hivenumber)
 	. = ..()
 
+	if(hivenumber == XENO_HIVE_NORMAL)
+		RegisterSignal(SSdcs, COMSIG_GLOB_GROUNDSIDE_FORSAKEN_HANDLING, PROC_REF(forsaken_handling))
+
+/obj/item/xeno_egg/proc/forsaken_handling()
+	SIGNAL_HANDLER
+	if(is_ground_level(z))
+		hivenumber = XENO_HIVE_FORSAKEN
+		set_hive_data(src, XENO_HIVE_FORSAKEN)
+
+	UnregisterSignal(SSdcs, COMSIG_GLOB_GROUNDSIDE_FORSAKEN_HANDLING)
+
 /obj/item/xeno_egg/get_examine_text(mob/user)
 	. = ..()
 	if(isxeno(user))