SPIGOT-7044: Modified RandomSourceWrapper to ensure random is not null before setting seed

By: Vatuu <21113232+Vatuu@users.noreply.github.com>

paper-server/src/main/java/org/bukkit/craftbukkit/util/RandomSourceWrapper.java

@@ -72,8 +72,10 @@ public final class RandomSourceWrapper implements RandomSource {
 
         @Override
         public void setSeed(long l) {
+            if (random != null) {
                 random.setSeed(l);
             }
+        }
 
         @Override
         public int nextInt() {