Ensures personalities are loaded before prefs are loaded (#93265)

## About The Pull Request

Aaaaa if you load fast personalities aren't instantiated so personality
loading wipes everything out.

I don't know the best way to ensure personalities are loaded before
anyone could load in unfortunately, so I just threw it in. Will need to
ask around.

## Changelog

🆑 Melbert
fix: Fixed personality wiping
/🆑

code/controllers/subsystem/processing/personality.dm

@@ -19,6 +19,9 @@ PROCESSING_SUBSYSTEM_DEF(personalities)
 
 /// Initialized personality singletons
 /datum/controller/subsystem/processing/personalities/proc/init_personalities()
+	if(length(personalities_by_type))
+		return // Already initialized
+
 	personalities_by_type = list()
 	personalities_by_key = list()
 	incompatibilities_by_group = list()