Ignore exception if Brigadier is not supported by the server (#1506)

This error occurs when another plugin/the server shades the brigadier library without relocation on pre 1.13 MC versions.

bukkit/src/main/java/me/lucko/luckperms/bukkit/LPBukkitPlugin.java

@@ -159,10 +159,12 @@ public class LPBukkitPlugin extends AbstractLuckPermsPlugin {
             try {
                 LuckPermsBrigadier.register(this, cmd);
             } catch (Exception e) {
+                if (!(e instanceof RuntimeException && e.getMessage().contains("not supported by the server"))) {
                     e.printStackTrace();
                 }
             }
         }
+    }
 
     @Override
     protected void setupManagers() {