Removing zstd module from sandbox

Signed-off-by: Sarthak Aggarwal <sarthagg@amazon.com>

sandbox/plugins/custom-codecs/build.gradle

@@ -1,28 +0,0 @@
-/*
- * SPDX-License-Identifier: Apache-2.0
- *
- * The OpenSearch Contributors require contributions made to
- * this file be licensed under the Apache-2.0 license or a
- * compatible open source license.
- *
- * Modifications Copyright OpenSearch Contributors. See
- * GitHub history for details.
- */
-
-apply plugin: 'opensearch.opensearchplugin'
-apply plugin: 'opensearch.yaml-rest-test'
-
-opensearchplugin {
-  name 'custom-codecs'
-  description 'A plugin that implements custom compression codecs.'
-  classname 'org.opensearch.index.codec.customcodecs.CustomCodecPlugin'
-  licenseFile rootProject.file('licenses/APACHE-LICENSE-2.0.txt')
-  noticeFile rootProject.file('NOTICE.txt')
-}
-
-dependencies {
-  api "com.github.luben:zstd-jni:${versions.zstd}"
-}
-
-yamlRestTest.enabled = false;
-testingConventions.enabled = false;