Fix FPS and other preferences not properly applying after reconnect (#61542)

Fixes #61515. Preferences were only applied on load_preferences(), which only fires when the preferences datum is created. Preferences datums are cached, and so load_preferences is only called the once.

code/modules/client/client_procs.dm

@@ -238,6 +238,7 @@ GLOBAL_LIST_INIT(blacklisted_builds, list(
 	prefs = GLOB.preferences_datums[ckey]
 	if(prefs)
 		prefs.parent = src
+		prefs.apply_all_client_preferences()
 	else
 		prefs = new /datum/preferences(src)
 		GLOB.preferences_datums[ckey] = prefs

code/modules/client/preferences.dm

@@ -329,6 +329,15 @@ GLOBAL_LIST_EMPTY(preferences_datums)
 
 	return preferences
 
+/// Applies all PREFERENCE_PLAYER preferences
+/datum/preferences/proc/apply_all_client_preferences()
+	for (var/datum/preference/preference as anything in get_preferences_in_priority_order())
+		if (preference.savefile_identifier != PREFERENCE_PLAYER)
+			continue
+
+		value_cache -= preference.type
+		preference.apply_to_client(parent, read_preference(preference.type))
+
 // This is necessary because you can open the set preferences menu before
 // the atoms SS is done loading.
 INITIALIZE_IMMEDIATE(/atom/movable/screen/character_preview_view)

code/modules/client/preferences_savefile.dm

@@ -163,12 +163,7 @@ SAVEFILE UPDATING/VERSIONING - 'Simplified', or rather, more coder-friendly ~Car
 		fcopy(S, bacpath) //byond helpfully lets you use a savefile for the first arg.
 		return FALSE
 
-	for (var/datum/preference/preference as anything in get_preferences_in_priority_order())
-		if (preference.savefile_identifier != PREFERENCE_PLAYER)
-			continue
-
-		value_cache -= preference.type
-		preference.apply_to_client(parent, read_preference(preference.type))
+	apply_all_client_preferences()
 
 	//general preferences
 	READ_FILE(S["lastchangelog"], lastchangelog)