respect CONFIG.PERSIST_BACK_LOCATION (in a more roundabout way...)

Author: John-Paul-R

src/main/java/com/fibermc/essentialcommands/playerdata/PlayerData.java

@@ -164,6 +164,10 @@ public void initializeRuntimeState(ServerPlayerEntity player, File saveFile) {
         // Revoke any abilities that shouldn't persist
         Pal.revokeAbility(player, VanillaAbilities.INVULNERABLE, ECAbilitySources.SLEEP_INVULN);
 
+        if (!CONFIG.PERSIST_BACK_LOCATION) {
+            this.previousLocation = null;
+        }
+
         updatePlayerEntity(player);
     }