Check the update folder exists before trying to use it

core/src/main/java/org/geysermc/geyser/extension/GeyserExtensionLoader.java

@@ -165,7 +165,9 @@ public class GeyserExtensionLoader extends ExtensionLoader {
 
             Pattern[] extensionFilters = this.extensionFilters();
 
-            List<Path> extensionUpdatePaths = Files.list(extensionsDirectory.resolve("update")).toList();
+            Path updateDirectory = extensionsDirectory.resolve("update");
+            if (Files.isDirectory(updateDirectory)) {
+                List<Path> extensionUpdatePaths = Files.list(updateDirectory).toList();
                 extensionUpdatePaths.forEach(path -> {
                     if (Files.isDirectory(path)) {
                         return;
@@ -181,11 +183,13 @@ public class GeyserExtensionLoader extends ExtensionLoader {
                         // Try load the description, so we know it's a valid extension
                         GeyserExtensionDescription description = this.extensionDescription(path);
 
+                        // Overwrite the extension with the new jar
                         Files.move(path, extensionsDirectory.resolve(path.getFileName()), StandardCopyOption.REPLACE_EXISTING);
                     } catch (Throwable e) {
                         GeyserImpl.getInstance().getLogger().error(GeyserLocale.getLocaleStringLog("geyser.extensions.update.failed", path.getFileName()), e);
                     }
                 });
+            }
 
             List<Path> extensionPaths = Files.list(extensionsDirectory).toList();
             extensionPaths.forEach(path -> {