PDA Messages are once again shown to non-observing dead mobs (#77750)

Current implementation uses isobserver for checking if we should send to
the player but dead players (who are still in their body) are not
observers and will fail that check.

code/modules/client/preferences.dm

@@ -473,14 +473,20 @@ GLOBAL_LIST_EMPTY(preferences_datums)
  * Arguments:
  * * client/prefs_holder - the client to get the chat_toggles pref from.
  */
-/proc/get_chat_toggles(client/prefs_holder)
-	if(!prefs_holder)
-		return FALSE
-	if(prefs_holder && !prefs_holder?.prefs)
-		stack_trace("[prefs_holder?.mob] ([prefs_holder?.ckey]) had null prefs, which shouldn't be possible!")
-		return FALSE
+/proc/get_chat_toggles(client/target)
+	if(ismob(target))
+		var/mob/target_mob = target
+		target = target_mob.client
 
-	return prefs_holder?.prefs.chat_toggles
+	if(isnull(target))
+		return NONE
+
+	var/datum/preferences/preferences = target.prefs
+	if(isnull(preferences))
+		stack_trace("[key_name(target)] preference datum was null")
+		return NONE
+
+	return preferences.chat_toggles
 
 /// Sanitizes the preferences, applies the randomization prefs, and then applies the preference to the human mob.
 /datum/preferences/proc/safe_transfer_prefs_to(mob/living/carbon/human/character, icon_updates = TRUE, is_antag = FALSE)