Fix guests spawning in naked (#2412)

## About The Pull Request

Add `?` operator to `alt_job_titles` accesses

## Why It's Good For The Game

Fixes #2209 

## Proof Of Testing

Spawned in as a guest with my proper equipment and title.
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<summary>Screenshots/Videos</summary>

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## Changelog

Nothing relevant to players

code/controllers/subsystem/job.dm

@@ -589,7 +589,7 @@ SUBSYSTEM_DEF(job)
 /datum/controller/subsystem/job/proc/equip_rank(mob/living/equipping, datum/job/job, client/player_client)
 	// SKYRAT EDIT ADDITION BEGIN - ALTERNATIVE_JOB_TITLES
 	// The alt job title, if user picked one, or the default
-	var/alt_title = player_client?.prefs.alt_job_titles[job.title] || job.title
+	var/alt_title = player_client?.prefs.alt_job_titles?[job.title] || job.title
 	// SKYRAT EDIT ADDITION END
 	equipping.job = job.title
 

code/modules/mob/dead/new_player/new_player.dm

@@ -249,7 +249,7 @@
 
 	if(humanc) //These procs all expect humans
 		// BEGIN SKYRAT EDIT CHANGE - ALTERNATIVE_JOB_TITLES
-		var/chosen_rank = humanc.client?.prefs.alt_job_titles[rank] || rank
+		var/chosen_rank = humanc.client?.prefs.alt_job_titles?[rank] || rank
 		if(SSshuttle.arrivals)
 			SSshuttle.arrivals.QueueAnnounce(humanc, chosen_rank)
 		else

modular_skyrat/modules/alternative_job_titles/code/job.dm

@@ -14,7 +14,7 @@
 	if(!ishuman(equipping))
 		return
 
-	var/chosen_title = player_client.prefs.alt_job_titles[job.title] || job.title
+	var/chosen_title = player_client.prefs.alt_job_titles?[job.title] || job.title
 
 	var/obj/item/card/id/card = equipping.wear_id
 	if(istype(card))