Fix PartySaving related NPEs (only save parties if they're enabled) (#4973)

Co-authored-by: Dieu <info@l4b.org>

src/main/java/com/gmail/nossr50/mcMMO.java

@@ -384,7 +384,8 @@ public class mcMMO extends JavaPlugin {
             UserManager.saveAll();      // Make sure to save player information if the server shuts down
             UserManager.clearAll();
             Alchemy.finishAllBrews();   // Finish all partially complete AlchemyBrewTasks to prevent vanilla brewing continuation on restart
-            getPartyManager().saveParties(); // Save our parties
+            if(partyConfig.isPartyEnabled())
+                getPartyManager().saveParties(); // Save our parties
 
             //TODO: Needed?
             if(generalConfig.getScoreboardsEnabled())

src/main/java/com/gmail/nossr50/runnables/SaveTimerTask.java

@@ -20,7 +20,7 @@ public class SaveTimerTask extends CancellableRunnable {
             count++;
         }
 
-
-        mcMMO.p.getPartyManager().saveParties();
+        if(mcMMO.p.getPartyConfig().isPartyEnabled())
+            mcMMO.p.getPartyManager().saveParties();
     }
 }