Fixed possible NPE for NullCommandSender

Co-authored-by: willkroboth <[email protected]>

Author: SB2DD

commandapi-platforms/commandapi-bukkit/commandapi-bukkit-core/src/main/java/dev/jorel/commandapi/CommandAPIBukkit.java

@@ -411,7 +411,7 @@ public BukkitCommandSender<? extends CommandSender> wrapCommandSender(CommandSen
 			}
 
 			final Class<? extends CommandSender> NullCommandSender = paper.getNullCommandSender();
-			if (NullCommandSender.isInstance(sender)) {
+			if (NullCommandSender != null && NullCommandSender.isInstance(sender)) {
 				// Since this should only be during a function load, this is just a placeholder to evade the exception.
 				return null;
 			}