SPIGOT-6605: Add method to access value of enforce-whitelist

By: md_5 <git@md-5.net>

paper-server/src/main/java/org/bukkit/craftbukkit/CraftServer.java

@@ -1518,6 +1518,16 @@ public final class CraftServer implements Server {
         console.setHasWhitelist(value);
     }
 
+    @Override
+    public boolean isWhitelistEnforced() {
+        return console.aN();
+    }
+
+    @Override
+    public void setWhitelistEnforced(boolean value) {
+        console.h(value);
+    }
+
     @Override
     public Set<OfflinePlayer> getWhitelistedPlayers() {
         Set<OfflinePlayer> result = new LinkedHashSet<OfflinePlayer>();